So I've been learning to paint recently and I drew up another Sans. I've been having an undertale thing recently, freaking sue me... I thought this'd be good practice or something, idk.

This is the first painting I've done in a while and it's easily the first I'm actually happy with. I suck at painting and I'm very serious on getting better at it. What do you guys think?
Any comment/critiques would be really appreciated.

Sans is from Undertale and belongs to Toby Fox.