As an Undertale fan, I cannot stop watching this. It's just too great, really, haha. I love how each character moves to the song, especially Frisk. I'm just worried about Papyrus messing up his jaw from the way he's moving his head, haha.
Even though I love this video, it does have it's flaws. Like Psychopath said, both Papyrus and Frisk have four fingers on their left hand and three on their right. Also, this is probably me just being nitpicky, but Papyrus is really hugging the center line of the road. Not a total issue, I would say, but it's something I noticed.
Also, the buildings in the distance don't eventually go out of view as Papyrus is driving down the road, which they should. Very unrealistic.
Finally, I don't know why you made it so one side of the barrier is a solid barrier and the other side is a railing. Both sides should be the same.
I would be more critical with this, like the two users below me, but I feel like this wasn't something totally serious. Just a fun, little loop no more, no less. Not to mention that I think Psychopath was being TOO critical. A few of the things he described as problems I don't even see and a few are just opinionated.
Overall, it's a pretty fun little loop, but it has a few issues. Like I said, I don't think this was a serious project, so I wasn't going to be overly critical about it. And even though it has it's issues, I'm going to be watching this at least once a day for a little while, haha.