I've been toying around with the idea of a volcano level, but I've been having trouble finding a good tileset. What do you guys think about this one?

Here are some suggestions for areas Castle Mountain Desert Snowy Plain Pirate Ship Underwater City.

I'm only using the premade stuff this time so I unfortunately don't have the freedom to make most of those, but I already have snow fields and deserts figured out. Thanks though

NKXXZ4AD. This is the key for the alpha. Please keep in mind that it's far from balanced, there's a some things that don't do anything and quite a bit has been changed.

I suggest putting rocks different BG layer from ground's in order to avoid seeing lava through the ground.

I'd suggest placing all rocks on their own layer (if you can spare one) and color that layer with a red tint with BGCOLOR.