Running the 5.2 MB .gif through Gfycat reduces the size to a 566kb .webm file, for example [1].

[1] http://www.gfycat.com/PartialBlissfulEarthworm#

I can halve the size of the GIF with a bit of lossy compression (https://pornel.net/lossygif http://compressor.io/compress), but a proper video codec or actual WebGL would be much better indeed.

Or an actual map, scripted to move.