Wow, that looks great! As you said, in various clips there's a couple of bumps, etc., but other than that, technically-wise everything looks pretty flawless. I'll try to be thorough:
Test 2 (camera movement): Maybe try to ease out a bit more.
Test 4 (running): (maybe) exaggerate the arm and leg movement just a bit more. It kind of looked like he was gliding.
Test 5 (quick pan): It seemed to ease in, then ease out, then move again, then ease out. It didn't look amazingly fluid, but it was still a good test.
Test 11 (slow pan): I would've liked to see more easing and the camera to stop, but I suppose because it's a montage it isn't exactly necessary.
Test 14 (self conflict 2): The muzzle flash wasn't that great... With your style of animation it may have looked better to have actually just attached a translucent Lego cone onto the gun. (also, the cartoon Joker's hair kept on moving.)
Test 16 (machine gun): That was actually much better with the 'real' muzzle flash than the former.
Test 17 (double slap): The second slap looked like it didn't have any force behind it.
Test 18:
Test 25 (death): Maybe when you just had the olive head-block on the body, you should have had a frame with a grey flat hair piece? (very nitpicky)
Test 29 (head bang): His arms should move to exaggerate the bang.
Test 40 (kicking the bucket): He seems to stop very abruptly, maybe his arms and back should've gone back a bit farther and then settled?
Test 44 (rimbledim): Hmmm... not sure what it is, but the walk looks too robotic.
Those tests really do look great, though. I'm being very nitpicky and am trying to be constructive.
Hope you can take some of this critique into consideration! Cheers.
Persist.