Nobody knows how many worlds there will be. I'm still trying to decide between 5 and 6 worlds. But world 4 takes place in space. It will involve:
1 New gameplay
this means
.rockets
.zero gravity puzzles
. gravity "pools"

2. Clever thinking

3. Skill

4. New enemies

The boss will be a robot called Spacerobo, which will be half spaceship half regular.