alot less frustrating than having a immovable enemy, but functionally no more interesting than a time limit. collisions would add a ton of depth to something like this including letting the enemy respawn, would probably open up a whole new dimension to the game
woah! now it feels alot more interesting having a enemy you can interact with, more than just a timer. it would be cool though if there was some mechanic to constantly bring them back to you so that you feel neck to neck tension. like a boost for those behind including the enemy. that would also be cool to do in impossible mode having to deal with both managing the obstacles and managing the enemy, all adding depth without any need to explain things.