I ran out of ideas, so I decided to make a vanilla version of my 24hosmw #12 contest entry (for reference, this entry did ask you to speedrun rooms within 4 seconds time limit).
I don't have retry system anymore (as FPZero has said "The retry system was the only non-vanilla thing I noticed and I feel that it was essential to this level's success."), and at least four judges out of five are aware of my 24hosmw #12 entry, but that's not stopping me. May as well have fun implementing something in vanilla when I was "challenged" to make my level without retry system.
--------------------Legacy ports zip
(now that those went down because Dropbox)