Incredibly cool!!
It doesn't seem to be working as expected with multiple layers if color mode is set to indexed... The transparent color doesn't show through to the layers below, but instead covers them up? (If the transparent color has opacity 0, it still does this, but the snapshot images just have big chunks of transparent space.)
(using Aseprite 1.3-rc9, aseprite-record v3.6.1)
Still though!!! Very helpful, and switching to RGB isn't much of a problem, so I'll DEFINETLY be using this!
I just pushed a new version that tries to work around the issue you described, one caveat is the snapshots are forced into RGB mode to work around the transparency not showing. This may cause incompatibility if you try to continue an in progress timelapse for an already indexed sprite. Please let me know if this update resolves things for you.