I hacked basically everything... You're in control of virtually every aspect of the game. (Excluded the story line itself, which was a tad too complicated to hack up).
Things this trainer offers:
- Infinite health (Regardless of how much your max health is)
- Max health (Sets to 255)
- Invincibility (Everything fazes through you, like you were just hurt. Bad: Messes with machine gun)
- Infinite booster
- Current weapon level (You can lock this to 1 or 3 with hot keys)
- Current weapon (Whatever weapon slot you're in, you can change its weapon with + and -)
- Infinite Ammo for current weapon (Regardless of max ammo)
- Weapon no longer needs ammo (Never runs out, even without trainer)
- Append a weapon to your collection (Max is five, uses hot key * )
- Inventory editor (Two drop down boxes; one is for slot number, the other is for item)
- A system to let you use the numpad to move around in large increments, which lets you walk through walls and speeds up the game
I've labeled it version 0.1 for now, in case I decide to make another. The only thing I can think of that I didn't hack is air, but drowning was never really a problem, correct me if I'm wrong.
Plus/Delta worth mentioning:
- Really speeds up replays for those like me who don't have that much time.
- When you lock your level at three, it only keeps the experience level high if it's already above zero. This way you can fire the Spur on full blast without the annoying jingle every second.
- Infinite health / Ammo won't set your max ammo, so you can cheat through one part, then play the rest fairly.
Not so positive:
- Cave story must be running under the name Doukutsu.exe for this to work. So run Cave Story, then the trainer.
- Doesn't save settings between runs, which can be good or bad.
On another note, the trainer is GPL. So any devote Mac users who can program a small interface and wrap the WinApi have slightly less work to do.
On that note, I disclaim any and all responsibility for anything bad that happens should this thing not work as intended. Shouldn't cause any harm, doesn't even do any file I/O, but if something goes wrong, I'm not responsible. (Though I'd still like you to report it here so I can fix it)
I tested the trainer myself, and can only hope it works for everyone else. Let me know if any of it doesn't work.
Trainer for Windows
Source for Developers