Maybe I'm missing something, but this seems to be a more boring version of Mazebert and, in my opinion, goes against the Mazebert style.
It's somehow a bloons TD gameplay with the endless feature. I've seen few people on discord experimenting about what they can do while removing their skill points (Mikhael is one of them AFAIK)
Eternal limbo refers to the player suffering in an infinite level with the enemy stats only keeps on increasing as every round passes so yeah. You're right.