[Hawkeye]

Does ePSXe as a debug mode that could work while running a game or demo? I think I read about this somewhere...

 

[sxamiga]

Not that I know of. The only way would be to keep the DOS window open at the same time as the game is running so that you could see exactally what the emulator is doing at any given time.
You might be able to accomplish this by running your game in a window. This would be the closest thing to debugging that i know of.
sincerely,
sx/amiga

 

[Betamax]

Yep there is a debugger built into epsxe accessed by the -debug option (if I recall correctly) however it is disabled in the public version so we can't use it.

 

[Hawkeye]

Does anyone knows if there is a good PSX emulator out there that as a built-in debugger that I could use?

 

[SimonMallion]

Maybe you could try PSEmuPro, that has debugging functionality built in.

 

[Adair]

I haven't tried it, but what about the debug menu in PCSX? Is it functional? Then again I couldn't get any of my games to work in PCSX. Probably just the games though.