Here are some of the obstacles and a few more types of platforms I have set up for now:
1. Spikes – fixed place.
2. Rotating spikes – comes in many sizes, can be fixed in place or moving in a sine, on this one I added a nice little little feature, I have 8 image points defined, one for each spike and on collision i pick the closest one to the player and pin him to it, pretty straightforward but cool nonetheless.
3. Metal weights – hanging from a chain and rotating, on collision I throw the player to the other direction to simulate impact.
4. Flying Bee-Bats, can fly in any direction, but usually in preset sine movement.
5. Following enemies – they will follow you if you get close enough.
7. Fans – player can use the UP/DOWN buttons for extra control while diving.
8. Gates and Levers.
9. Electric lines – functions like a jump/fall through platform with an electric current running up and down it.
10. Conveyor belt – standing on this platform will push the player left or right in a predefined speed.