JJ1
Best: Tubelectric 1? I love that one. Sucker tubes, much secrets, stupid spark enemies & good music.
Worst: Pezrock... Why? It's boring with crappy enemies + bad music. And deckstar boss level, which I hate becouse the boss is a crappy one too. Shoot a nuclear barrel to blast of devan... Ehh...

JJ2
Best: Badd Pitt - I love it becouse the huge areas, strong enemies, devan boss & for the music.
Worst: Rabbit in Training =D

I had completed orbitus 2, it was hard, but not unfinishable, just need to try much. =)