Pause the game, press backspace and type a cheat.

jjantilag - JJ3 uses more free memory to load every bit of the level and all sprites. That would solve the lag problem....

I doubt it would.

What would happen if a bigger level was loaded?

Wrong forum, sorry

With really big levels you would get amnesia errors when saving, the amount of events per area causes the lag.
I also think that amnesia errors can be avoided by giving more space for every savegame slot. Yet I think I'm wrong....

jjsd (jj self destruct)

jjrobot (creates a huge robotic machine that you jump into and fly through buildings and dominate the world!!)

jjmorph (includes eva earlong, a cat, devan and the checkpint thing (it hops around the place like the frog)

jjsing (makes the character sing)

jjfall (complete opposite of fly, you look lie you're falling even when on ground (jjfall again to disable).

~Jindo

What's the difference between self destruct and jjk?

jjpattern - Display the mod playing pattern on layer 8, without texture mode.

...Why would JJ3 use sprites anyway?

EDIT: Or give amnesia errors, for that reason?

What do you mean?

I mean JJ3 doesn't use sprites. Nor would AVs or Amnesia Errors be that common, as it uses a completely different engine.

Plus, if all the available memory were used , a level that would require more memory would fail to load, and the PC would crash.

Your cheat code loses.

Well.... err.... you see....*silence*

Yes, those cheats would be very useless indeed.