Crisis Cavern has introduced new enemies in the game. Mostly Neander-Pacs and Spiders which also appear in Pac-Man World 2. This level has a series of traps in it such as Rock Traps and Swing Traps. There is a huge button with a symbol on it (Possibly Anubis Rex) that trigger these traps. The symbol also appears all over the Ruins. It could symbolize something to do with the Ruins.
The Rock Traps trigger rocks to fall and crush Pac-Man. If Pac-Man steps on the button, jump away quickly before you get crushed. Once you get crushed you have a short time to escape before more rocks fall. If Pac-Man presses a button that triggers the Swing Traps, a swing with spikes on it starts to move fast and rock back and forth. If you get hit it could push you off the ledge, but you mostly just lose health. It is possible to avoid the swings once they are moving, you have to time your jumps though. Otherwise it could be hard to escape.
There is also another type of trap but that is only in Manic Mines.
Crisis Cavern has a dark environment to it and there are alot of Spiders. In some parts of the level there is lava. This could have been related to Into the Volcano on Pac-Man World 2.
There are also waterfalls in this level. This is the only level in the game to have waterfalls you can step in (besides Ghost Island).