I must disagree. Let us compare sprite sheets.

Devan can run left and right, jump left and right, stand still, stand still and shoot, warp, and turn into a demon.

Jazz can do all of this, except for turn into a demon, but he can turn into a frog and back, which Devan can not. He can also hang from things, hold onto swinging vines, bounce off of springs, jump straight up and down, spin through sucker tubes, be hurt, shoot while in midair, duck, shoot while ducking, walk, shoot while walking, rev up to run, use his special moves, buttstomp, hang onto a copter, fly around on an airboard, change directions on an airboard, be drunk from smoke rings, and probably several (many?) others I'm forgetting.

Not that I know why Devan would be added to MP but not SP.

Edit: Oh yeah, I guess Devan can fall straight down and sit dejectedly as well. But still.