I don't normally hack PS1 games, but what you asked about piqued my interest
.
Tried out Rogue Trip out in an emulator called No$psx (it has a built-in debugger) and used Cheat Engine to hook into that emu's live memory. Hacking the character select menu was super easy.
Big Daddy's screen can be switched to after selecting any mode/level. However, when I tried selecting him in levels other than Nuke York, he'd say something and loading would commence... only to fail around 3/4 of the way through
. The game freezes at that point. I was able to play as him in Getaway mode's Nuke York level though, which can't normally be done with the password method. As for 2 player mode, I wasn't able to get No$psx to emulate player 2's controller, so I haven't been able to test that out.
This might mean Big Daddy's character assets are bundled into Nuke York's level files to some degree. If that isn't the case, a much more powerful/complex hack may be needed to make him playable in all levels. More experienced PS1 hackers than me would need to look into it.
If you (or anyone else) is interested in trying out what I did, here's a brief guide:
- Launch No$psx (or any other PS1 emulator - probably doesn't matter) and start up Rogue Trip.
- Select any mode/level and go to the character select screen.
- Attach Cheat Engine to your emulator's OS process.
- In Cheat Engine, search for 0 while at Meat Wagon's screen.
- Press right to go to the next character's screen, and search for 1 in Cheat Engine. Repeat this process a few more times until you're down to roughly 4-10 search results.
- Add your search results into Cheat Engine's address list and modify their values to 14.
- Big Daddy's character select screen will now appear.
Notes:
- You'll need to search for character ID addresses again in Cheat Engine every time you restart your PS1 emulator.
- No$psx has its own built-in memory viewer (showing real PS1 memory addresses), but from what I can tell it doesn't seem very straightforward to use it to search for specific values in memory.