Okay, here's my progress on Crazy:
Confirmed all possible except following levels:
1, 3, 10, 14, 17
non-100% on following levels:
11, 15, 18, 19
Unsurprisingly, Crazy 17's issue is the time limit. I tried two methods so far, and I can't even get the worker lemming to exit in time.
I got 49/50 on Crazy 15, which is probably the max. I didn't do an optimal job on 18 and 19, I believe the maximum with my methods are 48/50 and 49/50 respectively.
Replays/screenshots for selected levels attached.