MSH TAG.

Marvel Super Heroes (1995) is the game the Marvel vs. Capcom series grew out of: the same heroes, the same Infinity Gems, super jumps and air combos, but one on one. MSH TAG gives it the tag system of Marvel vs. Capcom: Infinite. Each side picks two heroes. HP+HK tags the partner in, even in the middle of a combo, and a knockout sends the partner in instead of ending the round. The team shares one gauge, and the gauge buys the rest: a Counter Switch out of the opponent's combo, a crossover counter, a snapback, a double team with both heroes on screen, a team super, and a hyper tag from one super into the other. Blocking gets Marvel vs. Capcom's push block, free.

It's a patch for your own ROM. The installer takes the 951024 sets, msh (the one Fightcade plays), mshu, msha, mshjr1 and the Phoenix mshud, and a four-player version runs in a RetroArch core of its own. Give it your Marvel vs. Capcom ZIP too and double teams fight under that game's meteor sky: the installer reads it from your file, and nothing of it is in the download.

What's in v1

• Two picks per side. The first pick starts the fight. The button that confirms a pick chooses its colors: LP is the game's own, the other five are Marvel vs. Capcom 2's colors for that hero.
• Tag (HP+HK). The partner flies in at the opponent with its jumping attack while your hero finishes its move and leaves, so a tag can carry a combo. A normal or a special that hit or was blocked cancels into the tag.
• Counter Switch. HP+HK while you're being hit tags out of the combo. It costs two levels; with less, your red life and a tenth of your life pay for it.
• Crossover counter. B, DB, D + HP+HK while blocking: the partner comes in attacking, for one level.
• Push block. LP+MP+HP while blocking, as in Marvel vs. Capcom: the attacker slides away. Free, as often as you block.
• Snapback. QCF + MP+MK: a lunging hit for one level. If it lands, the opponent's hero is knocked off the screen, tumbling, and its partner is forced in.
• Double team. QCB + HP+HK, two levels: the partner lands beside you, one stick drives both, and supers are free until the TIME bar runs out. With your Marvel vs. Capcom ZIP, the stage gives way to its meteor sky.
• Team super. QCF + HP+HK, two levels: both heroes' supers at once.
• Hyper tag. HP+HK during a super: the partner comes in with its own super, for one more level.
• Life. Two life bars per side, each the size of the game's own, and both heroes' faces. The hero on the bench has a darker bar, a gray name and a darker face. Part of the damage stays red, and the bench wins it back.
• The gauges stay on top, under the life bars. In a double team the gauge grays out, its level reads infinity, and a TIME bar runs along the bottom of the screen.
• KO hand-off. A knocked-out hero lies down and the partner drops in, untouchable until it lands. One round per match; time over compares teams.
• The gauge stops at Level 3. Level 5 is the three-on-three convention of Marvel vs. Capcom 2 and 3; two-on-two games stop at three.
• CPU teams. Every CPU opponent brings a partner, and CPU teams tag too.
• Four players, one per hero, in the MSH TAG RetroArch core: a separate download.

The Infinity Gems, dashes, super jumps and throws work as they always did.

Four heroes in a two-hero game

Marvel Super Heroes runs the engine of X-Men: Children of the Atom, with its routines moved. It was written for two fighters: P1 at $FF4000 and P2 at $FF4400, $400 bytes each. The partners live in RAM the game never uses, $FF3000 and $FF3400, and the team state (who is on point, the side's mode, the bench's health and red life, the timers) at $FF3800.

A partner on screen is a whole fighter. The patch sets it up with the character's own setup routine, ticks it right after the stock ticks with its own buttons, registers it for the stock hit checks against the other side, pushes it, draws it with palettes of its own, and widens the camera so everyone stays in the picture. When it leaves, its slot is emptied: nothing ticks, draws, hits or aims at it until the next entry.

The tag itself is a swap. The partner is spawned in the free slot with the bench's health and color and jumps in. It homes in on the opponent: its jumping attack starts within 88 pixels or 12 frames into the entry, it crosses the screen at up to 22 pixels a frame, and against an opponent in the air it rises to meet it. The old point finishes its move and leaps out. When the entry is over, the two slots trade places, so the hero on point is always in P1's or P2's slot, where the stock game expects it.

The hyper tag and the freeze

A super freezes the fighters: while the flash plays, the stock game updates no one's buttons. The first hyper tag builds lost HP+HK pressed in the flash. Now the patch reads the controller itself while its own side is in a super and the freeze is on, holds the command, and starts the partner's super when the freeze ends.

The HUD

Each side has two life bars on one scale, each the size of the game's own: the point on top in the game's yellow, the partner under it in a darker gold, with its name in gray. Red life is its own segment. The partner's bar sits nine pixels nearer the middle, so its end meets the timer's V the way the point's does.

Both heroes show their faces. Under the point's portrait the partner's face peeks out, as if it stood behind: the lower half of its own portrait, darker while it waits on the bench, and the game's own low-life face once it's knocked out. A portrait is drawn in its hero's body colors, and the game keeps colors only for the heroes on screen. On screen the partner's face uses its body's palette. On the bench it gets a darker copy in a palette row the stock game never draws with in a fight (a census of twelve stages, supers included, found them), or, when those are taken, in an effects row it gives back whenever an effect needs it.

The timing took some care. A sprite the game lists shows two frames later, a palette write one frame later, so a face whose colors change with its sprite flashed the wrong colors for a few frames at every tag. The patch holds each palette row that changes meaning and writes it so it reaches the screen with the sprite list drawn for it. That cured the point's portrait too, which had shown the new face in the old hero's colors for two frames at every tag.

The gauges keep the game's place under the life bars, ten pixels lower to make room for the partner's bar. The gauge never goes past Level 3: the patch rewrites the table of maximum levels ($09EA90, one word per character) to 3, and the level reads 3 where the stock game shows infinity. In a double team the gauge grays out, its level shows the infinity sign, and a TIME bar runs along the bottom, under the game's own small TIME label: the gauge's shape, filled by the time left, while supers are free. The stock HUD draws under the fighters; the TIME bar is appended after the last record of the frame (the sprite list's end marker at $019BAC is hooked), so it draws over fighters and shadows, like the gems and the combo count.

The meteor sky

Marvel vs. Capcom draws its Cross background from a map it builds at boot: 32 blocks of meta-tiles, eight 512-pixel windows of a scrolling field of meteors and rocks, and a 36-step palette animation. MSH TAG builds the same sky when you install it, from your own mvsc.zip, so the download carries none of it.

The sky has to fit in a game that never planned for it. A census of the graphics tiles the game references (objects and all three scroll layers, over attract mode, supers and fights on ten home stages) found four runs of blank tiles that nothing referenced: 1,118 seats for 16-pixel tiles. Four of the eight windows, cut to the screen, need 986 unique tiles, and the installer copies them into those seats. The map of the four phases and the 36 palette records go into the free end of msh.06b, at $1F8000.

In a double team the patch points scroll 2 at a free part of video memory ($91C000, empty in every one of 120 fight dumps), turns scroll 1 and 3 off, and empties the stage's sprite layer lists, so only the fighters, the effects and the HUD stay over the sky. A VBlank hook right after the game's own register commit sets the scroll and the colors each frame: four phases six frames apart, the palette a record every four frames. When the last double team ends, the stage comes back.

The first version copied the sky's map into video memory when a double team started. On Fightcade's FBNeo core that made one frame run long, and a command pressed in it was lost: two double teams called at once got only one. The start of a double team is the busiest moment of a fight, with no idle time to spare on either emulator. Now the map goes in when each round's fight starts, half a phase a frame, where there's room, and the double team copies nothing. With the stage's sprites off, a double team under the sky even leaves the processor a little more idle time than one in front of the stage.

Six colors

The confirm button picks the colors, as in Six MvC2 colors for Marvel vs. Capcom: LK, MP, HP, MK and HK load Marvel vs. Capcom 2's colors for that hero from the Dreamcast palette banks (LK is LK, MP is HP, HP is A1, MK is HK and HK is A2), converted to the CPS-2's 16-bit colors with the game's own brightness.

Where the patch lives

The program is eight 512 KB ROMs, 03 to 10; the graphics and the sound are separate. The v1.2 payload is 24,252 bytes of 68000 code in the free end of msh.06b (from $1E8C00), with 101 guarded program replacements: short jumps into it and data. The four-player build has 24,684 bytes and 102 replacements. The confirmed Hulk followup adds a data box in msh.10b; its original followup box stays intact. (v1 had 22,820 bytes and 95 replacements; v1.1 had 23,888 and 98.)

The CPS-2 encrypts its program. On an arcade board each set has a key, and MAME's set holds it as a 20-byte file (msh.key). The encrypted range of Marvel Super Heroes is $000000 to $0FFFFF: the 03 and 04 chips. 05 and up are plain in every set, so the payload in 06b is the same bytes for all of them. The code hooks sit in 03 and 04, where the board decrypts instruction fetches. A plain data read returns the stored chip bytes without opcode decryption. Code and data must be checked in the view the CPU actually uses.

The keys are MAME's master keys from before key files existed, one per region and the same for both revisions. The proof is a rebuild: each master key, the watchdog instruction cmpi.l #$19660419,d1 and the upper bound $100000 make a key file with exactly the checksums MAME lists for msh.key, mshu.key, msha.key, mshj.key, mshh.key and mshb.key. Change a key bit or swap the watchdog words and none matches. So the installer ships each hook already encrypted with each set's key and needs no cipher of its own.

The payload reads stock DATA tables: the life bar tiles at $5E38, the gauge tiles at $607A, the name plates at $65DE, the portraits' faces at $669E and $671E, and the camera heights at $82804. Forming a table address relative to the program counter does not change a later read through that address into an opcode fetch. The patch and its guards preserve the DATA view, and copy most of these tables into RAM at the start of each match.

The installer checks before it writes. For each set it carries the SHA-256 of the bytes at every hook site and at 43 stock routines and tables (45 in four-player mode) the payload relies on, and it refuses a ZIP where any of them differs. For the sky it takes only the clean Marvel vs. Capcom files MAME lists, and a changed one is refused when you name it and skipped when it's just found next to your ZIP. The 951117 revision (mshj, mshh, mshb) has different code in 03, 04 and 05, and it's refused.

October 1: v1.2

Automatic tag-entry attacks can now be blocked standing or crouching. That rule applies to the attack the patch starts when the partner flies in; ordinary jumping attacks keep their native overhead behavior. In two-player mode, holding HP+HK to tag no longer carries those held attack buttons into the incoming hero's first move. Four-player partners keep their own pad input.

Hulk's crouching HP could hit once and miss its followup against smaller or crouching opponents. v1.2 uses a box with more outer and lower reach only after the first strike hits or is blocked. If the first strike whiffs, the followup keeps its original box. Timing, damage and reaction stay native.

The v1.1 fixes remain. Patch your clean original ZIP again; for four players, extract the full v1.2 RetroArch pack and let its launcher remake msh4p.zip. The Windows and Linux core binaries and source patch are unchanged from v1. Start-based taunt and Infinity Gem cycling remain unavailable in four-player mode.

Fightcade flicker remains open. The linked September 28 footage predates v1.1; the precise reported moment, current build and display settings have not been confirmed. Independent Windows/Fightcade installation and four physical controllers still need human testing. The tester checklist is also in all three packages and explains which files, settings and results to record.

September 29: v1.1

Testers played v1 on a stream on September 28. v1.1 fixes what they found, and two more bugs the fuzzing turned up.

• One round, from power-on. The round count is set once, when a game starts. v1 set one round only when team play was already on, and it isn't on the first game after the board boots: that game was best of three, and a knocked-out partner stayed out in round 2. Every game is one round now. A draw still brings the stock final round, and a hook on the round start ($8056) brings both teams back whole for it.
• The arcade route. When a CPU side loses, the stock marks its character as beaten ($CCC0). With teams that was whoever was on point, often the partner, so the route's opponent came back as the next match. v1.1 marks the team's first member.
• Tags swap records. A tag makes the partner's slot the point's. v1 copied the partner's $400-byte record over the old point's, so the old point's projectiles and effects went on reading and writing the new hero's data: Blackheart's Inferno state, Captain America's shield state, a hit's move data. v1.1 swaps the two records, and every object keeps the record of the hero that made it. What the retired record still owns is freed when the partner slot is used again. A random Blackheart fight with gems that crashed v1 runs clean on v1.1; it's the likeliest cause of the Blackheart crash on the stream.
• Character flags stay with the character. Each fighter record has a flag per character, set by that character's own setup and read as "am I Iron Man, Magneto or Doom" (flight, push boxes). v1 kept them with the player's slot, so a hero that tagged in kept the first one's. Juggernaut teamed with Iron Man flew with an Iron Man animation he doesn't have: invisible, then an address error in the sprite code.
• Palettes. On the Daily Bugle, the reflections in the windows use OBJ palette row 21, which v1 also lent to partners, so the reflections took the partner's colors: the "bizarro Spider-Man". On that stage partners now borrow rows 26 to 28, and a tag reloads the reflection row for the new point. Captain America's shield copies its owner's palette row when it's made. One made while he was the partner kept the partner's rows after he took the point, and showed the last partner's colors. A tag now moves every object off the partner's rows.
• A knockout on the way out. A hero knocked out while it finished its move and left went to the bench with no health and wasn't marked out, so the team could tag it back in. Now it lies down and it's out.
• The K.O. call. The round's message calls DOUBLE K.O. when both points have no health left ($6B7B0). On the stream Juggernaut went down, Hulk dropped in and knocked out Iron Man, the CPU's last hero, before he landed: "that was not a double KO". The win was Hulk's all along. The call now counts what each team has left, like the team KO test, so it's DOUBLE K.O. only when both teams are out.
• Gems. A partner starts with no Infinity Gems of its own. v1 cleared its inventory to zeros, and zero is the Power Gem, which a partner could then use without end. And a gem that's running keeps going through a tag: the gem and the inventory belong to the player, so its timer and effect move to the hero coming in. v1 ended it at the tag, and a Soul Gem stopped healing.

v1.1 needs your clean ZIP again: patch the original, not a v1 output. For four players the launcher sets a v1 msh4p.zip aside and makes the v1.1 one.

September 27: retail installer correction

The earlier v1 installer rejected legitimate clean retail ROMs at $005E38 with a “life bar tiles” error. That was our bug. It confused forming a table's address with reading its contents and used the wrong ROM view for several checks and runtime reads. This download fixes both; it keeps the complete ROM identity checks and every hook guard.

If you saw that message, download the installer again and patch your clean original ZIP. For four players, download and extract the full RetroArch pack again so the launcher uses the corrected installer. ZIP size alone does not identify a set. Your original ZIP is only read.

What got tested

• v1.1 gameplay: in MAME 0.264 on the Phoenix mshud and the patched Euro msh, 24 random two-player fights of 9,000 frames (1,230 tags, 38 double teams, gems now and then) had no crash or hang; v1 crashed in 1 of the same 24, and in 1 of 3 arcade runs against Thanos's team, which v1.1 clears 3 of 3. Scripted runs check every fix above: the first game's one round, the draw's final round, the arcade's beaten flag, the knockout on the way out, the returning shield on both sides, the Daily Bugle's reflection row on every frame of a fight with tags (v1: 2,132 of 2,292 frames wrong, v1.1: none), the K.O. call (a point down while its partner drops in and the other team's last hero down before it lands: K.O.; both teams out: DOUBLE K.O.), and a Soul Gem that goes on healing the hero who tags in (v1: it stopped at the tag).
• v1.1 four players: the MSH TAG core, unchanged from v1, runs a v1.1 msh4p.zip made from the Euro set in a scripted libretro frontend: P1 to P4 join, pick and drive their heroes, and ports 3 and 4 tag back.
• v1.2 installers: 19 of 19 fixture tests pass, including the optional sky, and all five real clean sets (msh, mshu, msha, mshjr1, mshud) pass both variants: ten cases. Python and the exact installer PowerShell body on PowerShell 7/macOS produce identical members. All 43 two-player and 45 four-player dependency guards per set reject changed bytes; eight negative controls produce no output. Original inputs remain unchanged.
• v1.2 Hulk and guard: the final Phoenix two-player build passes 220 Hulk cases across the roster, both sides, standing/crouching, hits, blocks, edges and whiffs. There are 25 explicit guard expectations across 27 two/four-player probes; two roster whiffs are excluded from guard success claims. Ordinary jumping overheads and independent P3 input remain available.
• v1.2 regressions: nine quantitative scenarios pass again, covering rounds, the CPU beaten flag, draw/bench restoration, exiting-fighter KO, identity flags, shield colors, reflections and Soul Gem carry. K.O. and DOUBLE K.O. banners also pass visual review. These are bounded diagnostics; the longer v1.1 fuzzing above is historical and was not repeated as a new long-session soak.
• v1.2 four players: the final installed Euro msh4p.zip passes scripted logical ports 1–4 joining, selecting and tagging out/back with correct ownership, empty first-partner gem slots, and team inventory continuity at the slot swap. Both sides' double teams and all eight TIME-bar checks pass. All five copied HUD/camera tables match the clean ROM before and after tags. These native runs use ordinary pad inputs and read-only RAM in a local macOS build of the published MSH TAG core. The MAME regression fixtures declare their setup writes.
• Historical v1 footage: the clips and original broad feature tests used the Phoenix build in MAME and FBNeo, including the optional meteor sky. They do not show the new v1.2 fixes.
• Still unverified: independent Windows/Fightcade installation, Windows PowerShell 5.1, cmd.exe and drag-and-drop, the Windows core on Windows, RetroArch UI and online play, four physical controllers, real hardware, and native gameplay on the USA/Asia/Japan retail builds. Their installer coverage does not establish native gameplay coverage. Use the tester checklist for the independent handoff.

Credits

To the testers on Discord whose notes on MvC1, XCOTA TAG and SSF2T TAG shaped this one: incoming partners you can block, color select, four players, and installers that explain themselves. And to Loïc "WydD" Petit, for his CPS-2 hardware research (CC BY 4.0).