Okay, finished the cave diving and I have to say, that was fun! So far I'm finding the interactions with the characters to be funny and cute. Nonetheless, I'll go over some things I've encountered.
The wave system can be easily abused depending on how you go about things. if you focus your build away from the slimes, they can't find the buildings to attack. The pink slimes are a nice addition and prevent the abuse of using the platform in the middle to create an accumulator elevator or something of the sort. While small in the grand scheme of things, I like this new breaking the mold of what we're used to. I can't wait to see what comes forth from the caves as the verticality can be used to create fun obstacles.