Action Replay
The cheat cartridge
The hardware cartridge series that enabled game freezing, cheat creation, and memory manipulation across Commodore 64, Amiga, and consoles - controversial but widely used.
Action Replay was a series of cartridges and devices produced by Datel that enabled users to freeze running software, search and modify memory, create cheats, and save snapshots. Available for the Commodore 64, Amiga, and various consoles, it became the go-to tool for cheat creation and—controversially—software backup.
Fast facts
- Manufacturer: Datel
- First version: ~1985 (C64)
- Platforms: C64, Amiga, SNES, Genesis, others
- Function: Freeze, cheat, backup
- Reception: Hugely popular
- Controversy: Piracy implications
What was actually on the cartridge
The Action Replay is remembered as a cheat device. Datel’s own command summary reads like a debugger’s manual, because that is what it is.
D |
M68000 disassembler |
C |
Copper assembler/disassembler |
E |
show/edit chip registers |
SPR |
show/edit sprites |
F |
search for string, case-sensitive |
COMP |
compare memory blocks |
LM / SM |
load a file to memory, save memory to disk |
PACK / UNPACK |
compress and expand a memory region |
RAMTEST |
check a memory block for hard errors |
One entry in the monitor list is the whole product in miniature:
SETEXCEPT: SET EXCEPTION HANDLER (NO MORE GURU)
The cartridge installs its own exception handler so that a crashing program drops into the monitor instead of a Guru Meditation. A tool sold to people who wanted infinite lives shipped with a working answer to the Amiga’s most famous error screen.
Infinite lives is a code search
The trainer is not a value freeze. It is a search for a kind of instruction:
TF: SEARCH FOR DECREMENTING OPCODES TFD: SEARCH AND REMOVE DECREMENT OPCODES
The command syntax describes the workflow: TS STARTLIVES begins with the count
the game started at, T AKTLIVES continues with the count now, and between them
the cartridge narrows down which address is the counter. Then TF finds the
instructions that decrement it and TFD removes them.
So the cheat is not a poked value the game can write over — it is the subtraction taken out of the program. (The manual gives the commands and their arguments; reading the two-step narrowing off that syntax is this Vault’s, not Datel’s.)
A virus scanner in a cheat cartridge
The command list has a section that has nothing to do with games:
VIRUS COMMANDS: VIRUS: SEARCH VIRUS IN MEMORY KILLVIRUS: SEARCH AND REMOVE VIRUS IN MEMORY
Bootblock viruses spread on the Amiga through exactly the swapped, copied disks
this cartridge was built to make, and Datel shipped detection and removal in the
same product. The disk section carries the other half of that job — BOOTCHK,
DATACHK and BAMCHK set a correct bootblock, data and bitmap checksum, which
is what a disk needs after something has been removed from it.
Platform versions
| Platform | Version | Era |
|---|---|---|
| C64 | Action Replay | 1985+ |
| Amiga | Action Replay I/II/III | 1988+ |
| SNES | Pro Action Replay | 1992+ |
| Genesis | Pro Action Replay | 1992+ |
Capabilities
| Feature | Use |
|---|---|
| Freeze | Stop any program |
| Cheat search | Find value locations |
| Poke | Modify memory |
| Save | Snapshot to disk |
| Monitor | Disassemble code |
| Fast loader | Speed disk access (C64) |
C64 Action Replay
The original version featured:
- Freeze button (asserts NMI on the 6510, capturing the running program’s state into the cartridge’s RAM)
- Fast loader (turbo tape/disk)
- Memory monitor
- Sprite viewer
- Cheat creation tools
The cartridge maps its own ROM and RAM into the C64’s address space when the freezer fires, swapping back out on resume. Same architectural pattern as the Multiface for Spectrum.
Action Replay VI
The most comprehensive C64 version (Datel, 1989) bundled:
- 32 KB of cartridge RAM and 16 KB of ROM
- Full machine-code monitor with built-in disassembler
- Sprite editor and graphics viewer
- Disk fast loader (~5× speed)
- “Picsave” — convert any frozen screen to a multicolour bitmap file
- “Tapesave” — turbo tape backup of frozen programs
AR VI was the canonical late-era C64 cracker tool; many of the era’s “+8” / “+12” / “+99” trainer versions were produced with it.
Amiga Action Replay
More sophisticated:
- Full 68000 monitor
- Disassembler
- Memory search
- Copper list viewer
- Disk tools
Console Versions
Adapted for different markets:
| Platform | Focus |
|---|---|
| SNES | Pre-made cheat codes |
| Genesis | Game enhancement |
| Later | Code entry, not discovery |
Cheat Discovery Process
Similar to Multiface:
- Note value (lives, energy)
- Search memory for that value
- Change value in game
- Search again
- Identify correct address
- Modify to desired value
Controversy
Action Replay existed in grey areas:
- Legitimate: Cheat creation, development
- Grey: Backing up owned games
- Illegal: Software piracy
- Response: Publishers hated it
Legacy
Action Replay democratised game modification, creating the cheat code culture that would eventually become mainstream through console devices like Game Genie. It proved there was demand for player control over game difficulty.