This entry was really fun and especially addictive. It's got that "just one more try" magic.
I don't play a ton of platformers but I found it very funny and entertaining that I could jump off of the air. The platforms are kept relevant by the fact that jumps off of them work much better; I found that mechanic fun.
I don't think it's particularly on-theme; I cannot tell what's different per-run. If you switch it to 'Gamer' mode (because there's so little room for error) it becomes very apparent that the platforms and enemies are in the same places every time. So, endings are not beginnings in any way that they are not in a normal arcade game with levels and one life.
One last thing I'll say is that in game jams, menus often fall by the wayside - there's just not time for them - and so I particularly admire this entry for having easy-to-use, complete menus at start and on pause!