I really like the mechanic and I think it can make an interesting game. I do have some issues however with the feedback the player is receiving and think this concept might work better as a third person game. Reasons for this is, activating the main mechanic takes away vision away from the player, the player has no idea where they are exactly or where to go, this makes it frustrating to go through the level. If it were a third person game, you could see where you enter the ground and how far the next platform is, this already gives plenty of more feedback than first person.