Wizards & Warriors X: The Fortress of Fear

Game Boy Rare 1990
Cheat code
Uncapped lives: enter [heart]-2-[heart] on the Scroll of Honour Undocumented

The known cheat for this game is entering W-[heart]-W as your name on the high score screen to start with 6 lives. But the code at 0x2DF4 checks for a second name that no cheat database lists: [heart]-2-[heart]. This sets a flag that removes the 9-life cap entirely, letting extra-life pickups push you past the normal maximum.

2DD4 LD HL,$C31F ; load high-score name pointer 2DDA LD A,($C002) ; 1st character tile 2DDD CP $EF ; 'W' in tile encoding 2DDF JR NZ,$2DF4 2DE1 LD A,($C006) ; 2nd character 2DE4 CP $D4 ; heart symbol 2DE6 JR NZ,$2DF4 2DE8 LD A,($C00A) ; 3rd character 2DEB CP $EF ; 'W' again 2DEF LD A,$03 2DF1 LD ($C2F6),A ; known: W-heart-W = 6 lives 2DF4 LD A,($C002) 2DF7 CP $D4 ; heart symbol 2DFB LD A,($C006) 2DFE CP $CA ; '2' in tile encoding 2E02 LD A,($C00A) 2E05 CP $D4 ; heart again 2E09 LD A,$06 2E0B LD ($C2F6),A ; NEW: heart-2-heart = uncapped lives
ROM
0x2DF4 - 0x2E0D
Flag
$C2F6 set to $06 removes the 9-life cap on extra-life pickups
Verified
Ghidra SM83 static analysis + cross-reference with known W-heart-W code
How to use: On the Scroll of Honour (high score) screen, enter the heart symbol, then the number 2, then the heart symbol as your 3-character name. Start a new game. Extra-life pickups will now push your lives past 9.

Trouble Shooter

Mega Drive Vic Tokai 1992
Hidden feature
Hidden stage select: Player 2 holds Start+C+Right on title screen

The title-screen handler at 0x480C checks Player 2's controller for a specific button combination. If P2 holds Start + C + Right (byte $A8 in the input register at $FFFFF605), a hidden stage select becomes available. This gate was found by decompiling the title-screen state machine and tracing the branch that was never taken in normal play.

$480C FUN_0000480c: ; title-screen handler ... MOVE.B ($FFFFF605).w,D0 ; read P2 input CMPI.B #$A8,D0 ; Start+C+Right? BNE.W skip_stage_select ; if match: enable stage select
ROM
0x480C (68000)
Input
P2 controller: $A8 = Start + C + Right held simultaneously
Verified
Ghidra decompilation + mednafen (visual: "SELECT STAGE" appears)
How to use: On the title screen, have Player 2 hold Start + C + Right on their controller. A stage select will appear.
Binary patch
Always-on stage select patch

We rewrote the title-screen handler in place (92-byte footprint, no code cave needed) to show "SELECT STAGE" and a number on every boot. Player 1 presses A to advance the stage number. The original P2 button gate is bypassed entirely. Header checksum recomputed at 0x18E.

Patch
Rewrites FUN_0000480c (92 bytes in place)
Input
P1 A button (BTST #6,($FFFFF603).w) advances stage
Build
build_stage_select_patch.py

Battle Mania Daiginjou

Mega Drive Vic Tokai 1993
Hidden feature
Obscure stage select unlock via BGM sequence

The Options screen BGM selector hides an unlock sequence: play SILENCE x4 then NOTHING 13 x3. This builds counters at $FFFFFE3A/$3B; when they reach $0403, the new-game routine at $295C2 unlocks a stage select screen instead of starting Stage 1. While documented on Sega Retro/TCRF, the RE confirmed the exact mechanism and enabled a one-byte patch to bypass it.

$295C2 CMPI.W #$0403,($FFFFFE3A).w ; check unlock counters $295C8 BNE.W $296D0 ; skip if not unlocked ; fall through to stage select screen
ROM
0x295C2 (68000, 1MB ROM)
Counters
$FFFFFE3A = SILENCE count, $FFFFFE3B = NOTHING 13 count
BGM table
ROM 0x28BB2
How to use: In Options, cycle the BGM selector to play SILENCE four times, then NOTHING 13 three times. Exit options and start a new game. A stage select screen will appear.
Binary patch
Always-on stage select (NOP the BNE)

The simplest possible patch: NOP the conditional branch at $295C8 so the stage select always shows on new game, no BGM sequence needed. Four bytes changed, checksum recomputed.

$295C8 66 00 01 06 BNE.W $296D0 ; original: skip stage select $295C8 4E 71 4E 71 NOP; NOP ; patched: always show it
Patch
0x295C8: 660001064E714E71
Checksum
$9333$C90F
Build
build_bm_stageselect.py