I had fun with this game, it reminds me of the boat levels in half life somehow, which is a good feeling. The levels flowed nicely, and I never felt like I didn't know where to go.
Thoughts and comments:
>Some better kind of aiming would feel nice, especially on things like the spear gun
>A few levels felt a little too big, and could maybe use some more hidden collectables to make it feel less bad when you fall off and needing to backtrack
>The enemy variety was nice, and their AI was very solid to play against
>Liked the upgrade system that I saw, felt good when I found one
I like piloting the boat a lot, but it kind of felt like a side note to the gameplay. Mainly I'd pull up, do the level, then ride the boat out. I'm sure you have stuff like this planned, but levels were you need to stay on the boat, multi-tasking driving and fighting would be cool.
My main gripe was the final boss (Tribal leader) was way too hard. His final form had an annoying tendency to jump and hit a pillar in the arena, instantly triggering the damage and killing you. Even then I could never quite do enough damage to win the fight. See the footage, I spent probably 20 minutes on him.
Recording of gameplay: