Hey Arca, glad to see you're still working on that game of yours. It's the game with those bodies/entities, right? I remember one of the first was this blue gollem looking monster.
The battle background looks great. The snakes and Arcanum look a bit too simple, though. Unless it's the style you're going for, I'd add a few stripes here and there, even if it's without new coloring. Maybe some on the snakes for when the skin folds, or add some random dots. I like Arcanum's face, but the legs could be a bit better. Maybe it's because he's wearing (awful xD) short pants, but it looks like he doesn't have any hips. :P
The tileset, on the other hand, is superb, imo. I love the way you made the little rock 'bridge' on the ceiling, below which the player can walk. Does that mean the outer cave wall isn't an autotile? Or did you place the rock 'bridge' on a layer above it, and add black with it to cover up the autotile on both sides? By the way, it would look good, imo, if you added some stalactites (the little V pointing rocks hanging from the ceiling) and made an outer cave wall border around them, to show that they're actually hanging from the ceiling. Just a thought. ^_^ My only complaints are the main floor texture and the sand at the bottom. What is that at the bottom anyway? It's colored as sand, but the sand is so clumped together it looks more like rock. As for the floor texture, there are a few stones in the middle of each tile which are highlighted (I believe there are 4-5, in a reversed C). This makes for a rather odd pattern. Perhaps it would be better to leave the highlight out or give it to all rocks. I always find it a bit annoying to see the same pattern of something that stands out in each tile. :P