Indeed, mountain grass, as we're calling it, is actually more like moss than grass, since it's growing in a less fertile environment. Although carpet-y moss is justified in the situation, the resemblance to the inside of a 60's era Volkswagen is less so. It needs to have some sort of anchor point, like parts of the grass drooping over the side, etc, to make it look less uniform, perhaps.

A white outline would hinder this piece more than it would help, I'm afraid.

Your reaper piece has a cool character concept going for it. I'd say kick the resolution up and give him some more personality, the costume deserves a face. It's a really interesting twist on the generic reaper cliche.

the back/right leg (our right) does not seem to be making the same motion as the others, while it walks. Almost like it's limping..  You need to make sure you have it at this angle, in one frame ---> /
right now it only appears at this angle --> \     all the time, while the others go through both angles, creating the illusion that it's actually preforming a walk. Looking much better though now, great improvement.

edit: i really hope that made sense, i am on my laptop, and i haven't a gif editor to do an edit. also, finish davey jones! the lineart is really good.

You really have to play the game to see how the characters pop out, there is so much freakin' parallax going on that it's easy to tell where the player is, at most times. Personally, i like number 3 the best, while the one in the screenshot seems to have a face that fits in better with the main character.