Also you have single pixels t the bridge thingy in the background! FAIL!

ack!
fixt

in addition to what  Ryu said, the chick's feet look as though she's standing on uneven ground.

in agreement with what Ryu said:
the knifehand looks real wierd and...bulky? compared to her other hand.
Maybe people have different proportions for their hands, but that little bunch of meat on the outside of my hand beneath my pinky is wider than my actual pinky by just a little bit. Of course it's not very defined either.

those are the most badass renditions of mario characters and creatures I have ever seen, B.O.B.
Toad frightens me.
Erm, if I may:
seems weird how some creatures have darker outlines than others even in the outlines version. like the koopas as compared to mario & co. Bob-omb especially stands out because of his thinness.

and is that...is that f'kin Yoshi!?

Likewise, I didn't look through the whole aforementioned thread, but I really liked this li'l gem: Magical Pop'n

edit; looked through the thread and saw it. Oh well, it's worth mentioning twice.