It would be cool if there were multiple levels in the world. It wouldn't have to be a large number, say just adding sky and underground where the visibility rules and collisions were affected.
Things in the sky could be seen further away and could see further away.
Things underground would be invisible & couldn't see anything.
Collisions only happened at the same level
* Collisions underground cause more damage, but less knock-back
* Collisions in the sky do more damage and send the critters to the ground.
It would be cool if there were multiple levels in the world. It wouldn't have to be a large number, say just adding sky and underground where the visibility rules and collisions were affected.