The drop from the dam is great until your boat hits the water with a small splosh. I think it should have a larger splash with some particle effects and an accompanying sound.
Sometimes the loops and rolls in aerobatic events don't register after you do them. I had to do an outside loop 3 times before it registered on the checklist.
Collision detection needs some tweaking, especially with boats. There were a few times I ghosted through other boats instead of crashing into them.
Checkpoint markers have unpredictable collision physics. Sometimes, they completely stop your forward momentum. Other times they only slow you down a small amount.