Very impressive game. I'll give it a high score despite some unfortunate playability issues. The game froze requiring me to refresh the page twice. The first time was right before I reached the masked man, and the second time was after I had nearly cleared Forest02 and had gone back to Forest01 to try and kill the T-rex, and that time the freeze was accompanied by loud overlapping noises. Since the game doesn't save progress between refreshes, I guess I probably won't finish it.
EDIT: I did end up finishing the demo because the save system started working and the crashes became less frequent. Despite all the locked-off areas, it still ended up being considerably larger than I expected. It was too bad the whole village was destroyed right after you went through it and possibly even invested in it. I actually started a new game because I had remembered one of the huts could teach you to craft firestarters, but I hadn't noticed that they were locked (which I assume is to prevent players from exploring beyond the bounds of the demo).
One of the most frequent glitches I encountered is that it looks like you're splashing in water when you're not in the water, so I'm wondering if it's possible that it triggers the effect for you when your pet goes in water