Knock! Knock! is a very long and hard, altough very fun level. It is optional, you have no further objectives than finishing the level. It has a day-night cycle, but not the ordinary way. You have to use doors to switch between day and night. There are several gags in this level, when you open a door. You can see a coming train, a showering girl or just a simple brick wall. It doesn't have too much enemies, but a lot of obtacles, thats why it's hard.
You can get here with a remote that can be found in the Rock It! level.
Only one: Use the doors to escape!
- Big Eye Guy
- Moving Spike
- Moving Platform
- Falling piano
- Falling safe/anvil
- Surprise boxing glove
- Bouncer star
- Disappearing moon
- Amber balls
- This is the only level where teleporters don't work immediately, but also you have to open the door covering the teleporter first.
- This is the only level that has a day-night "cycle". However it's not real cycling.
- This level is optional, just like the Planet X levels. You don't have to complete them to finish the game.