Cave crock things that sing

Well, unfortunately I noticed upon scanning that the top guy has some decently poor perspective issues!

However, I just set out to try a quick rendering method on top of a sketchbook page and tried it out regardless. I think that makes me a bad artist.  Maybe.

Haven't dug into details in a while, so it was fun.  With the above mentioned self critique and speedy execution in mind, any helpful suggestions?