The concept of running around in a semi-open island world with a boat and guns is actually really fun. Enemy death animations are well-done and the combat is satisfying. There are a handful of things I would critique though:
1. Hitscan weapons have no spray, so I could cheese enemies from 1000 yards away just by clicking on them with the pistol
2. All sounds seem to be audiostreams setup on the player camera; since its a 3d game you should use 3d audiostreams and place them positionally where they make sense. All the sounds of enemies making noise or throwing spears is always perceived as though it were next to the player's head no matter how far away the enemy is
3. Player movement and speed is nice and responsive though I think the jump physics should give player more control in the air and have less momentum
4. The mash up of enemies with 3d models and 2d sprite models is jarring. the color schemes aren't coordinated and the theme is inconsistent.
5. Auto-save when approaching islands can trigger at weird times and leave you in bad spots for reloads.
Overall I think some touch ups on the worldEnvironment would go a long way; more dynamic lighting/commitment to one art style/brighter blue sky/water etc. A shader effect on the water to create some waves would also give more of the feel of being on open water rather than in a big swimming pool.