What are the cheats in super smash flash

There are no cheats for this game. However, there is a glitch people use to go through the Adventure and Classic modes.
When on any stage of one of these modes, right click on the game screen, then right click again and press Play. It will skip the level.

This glitch does not work on the Target Test stage, it will only replace your character's targets positions with another characters target positions. After you complete Target Test, however, you can resume skipping levels.

If you skip while fighting a yet to be unlocked character, the game will assume you lost, taking you directly to the credits.