Thanks guys, that’s exactly the sort of feedback I needed.
I think maybe the big problem is with the way the clothes burn off all of a sudden at the start. It’s one of those things, everytime I see it I think “it’s not working”, but then another voice says “hey but his burnt flesh looks cool!”. I knew I’d have to fix it… just needed to someone to tell me. 
The burn matte for the clothes is the same but offset in 3D space. I’ll probably change so the clothes burn off with the flesh, but offset slightly ahead in time (3-4 frames) (so the burn reveal each layer as the one above burns up), so it’ll be all “one” effect.
Jozvex - good pick up about the gravity at the end - it’s half earth gravity. I kinda like the slo-mo feel, but I’ll keep playing with it. I’d like to “overlap” the final part with the “burn” part, but I can’t think of a particularly good way of doing it right now, as it switches from a rigged char to a hard dynamics on a pre-posed skeleton. :shrug: