Here's one of my last suggestions for now
what if you wanted to show off a trap or an exit that's animated for something you're working on?
An export as gif feature wouldn't be too bad
GIF is a poor choice given that it only supports 256 colors, whereas NeoLemmix supports full 32-bit. APNG is a much better choice, though I'd have to find out how to create an APNG file (and then there's the issue that some browsers don't support it).