Gate to The Loop: Found in level 2 (1-2)
Like a ferris wheel.

Gate to Kolle: Found in level 3 (1-3)
Use your head.

This one can be done a couple ways. It's easier to complete it in single player co-op, lag makes it difficult (but not impossible!) to achieve with online play.

Gate to Spier: Found in level 4 (2-1)
Back and forth and back.

Gate to Self: Found in level 6 (2-3)
Mind your head.

Gate to Ironman: Found in level 7 (3-1)
Juggling ibb up.

Gate to Lim: Found in level 9 (3-3)
Suspending in bubbles.

Gate to Eggermont: Found in level 10 (4-1)
Perseverance.

Gate to Liefhebber: Found in level 12 (4-3)
Tiktak u-turn tiktak warp.