I am here to confirm that I indeed suggested colourful laces. It was me.
I felt obliged to make an edit, but really this is just utterly amazing. Beautiful work. 10/10.
Thanks!

My edit does one majorly important thing: removes the silly, blank, first frame. Seriously, what was up with that?
I darkened your laces slightly in places, because I thought it might help with readability, but really it's much of a muchness.
The silly blank frame was a result of saving with a background layer in Grafx2. I guess I should avoid saving GIF's with layers? I like what you've done with the darkened laces, I gave it a try and I'm happy with it now:

Please make more stuff and I look forward to your sloth skating game. 
I hope you don't raise your hopes too high for that

Wow this is perfect. The only thing I'm worried about is that the scale is too large for an actual game. Once you factor in the size of the entire character. Unless you are designing 1:1 for high res which is a little crazy that you are doing pixel art for in that case. I suppose you might get away with 1:2 it's hard to tell as of yet
I agree, it is way too big. A boot this size would make the sloth of
SF3:3S proportions.
My drawing and animation skills aren't up for that yet, so I'll keep this big skate for something like an inventory icon. I'm going to try to tackle the sloth sprite in 32x32 I think.

I've started a sloth sprite, but I'm not happy with the proportions, the arms, the skates, the lack of chest fur, and my main worry: he is not very cute or abstractly iconic like Sonic or Mario or Quote. I guess I am worried he is a boring design?
I mean, I think the reason Deviant Art is full of sonic drawings owes something to Sonic's solid character design. He's more abstract, thus instantly recognizable and easier for kids to draw; and he has a personality.
A regular sloth's personalty might be slow and boring, but this is not a regular sloth. This is a sloth who dares to don skates. (A real sloth probably can't stand up on his own without hanging on to something, but I'll stretch it here.)