Great game! It was fun to figure out the mechanics of the weapons and health items, and while I wasn't sure of how to repair the time machine at first, the check marks once I had enough materials cleared that up. I like the puzzles of knowing where to stand and how to get a couple last tricky items too. The art is nice too!
I did manage to clip outside of the world in one playthrough and then couldn't get back in. Not sure quite how - I think I stood somewhere on an edge that wasn't valid in the prehistoric time and then got nudged out. That's a rare issue though, so this was still a lot of fun!