Some of these are really impressive. There have been several surprises where the developer(s) went the extra mile in ways that are surprising. Like in Lossst, when finishing a level, it'll zoom the camera to the next door and back to the worm. It's amazing that someone working within such a tight limit can think, "I know, we'll do this nice zooming thing which has no real relation to game play but will feel nice!"

JS has gotten incredibly concise in recent years. I've noticed it on codefights.com, where a lot of the shortest entries are JavaScript (and very few are Perl, which surprised me, due to Perl's long golfing history). I'm constantly struck by how tightly all the pieces work together these days and how much you can do with so little.