The animation and backgrounds were all really great. I really liked the visuals and sound effects you threw in, they really tied the whole cartoon together. Tails running up to sonic was seriously the funniest shit. The voice acting was decent too.
I will say though I don't think the memey stuff wasn't good for this (WHAT ARE THOOOOSE, sanic, rustling jimmies). I thought it really took away from the quality of the whole animation. Seriously, "what are those" joke came out of nowhere and I feel like you could've done more with the Shadow bit. Plus, canned sound effects (such as that door opening sound effect at 1:24) should be avoided. I know it's tempting to use existing stuff like that, but you might want to look deeper for sound effects which are less well known already. It can ruin the immersion viewers have to hear stuff like that.
As for the ending, i think it would've been a lot better if you just cut it after tails said "too slow" to end with more of a shock value, rather than do the whole seinfeld thing, which I'm pretty sure everybody watching has seen parodies of already.
All in all, I liked this cartoon and hope to see more from you. You draw very well, and I like your style. Keep it up.