Does it seem to work properly? It ran ok on Google Chrome which I used. The game was created in Unreal, It was cool to see a WebGL game of Unreal, I can't find an option resulting in using Unity instead for WebGL, any tips would appreciated. 

Is it any fun? Yes, but I am rubbish at playing these type of games. Reminds me off Dinsour game by Google

What would make it better? You can make an easy mode

I don't think catching the batteries are worth it, the hesitation sometimes causes me tog et splattered. I think the best (although) slower strategy is to just jump on everything, that makes the game too easy imo.

Maybe make it so that the batteries refills a stamina meter or something, not catching enough will cause the drill to catch up to you. If you go with this idea then you could also add a new projectile (some goo thing?) that is faster than the other projectiles. It will not kill you, but it will drain your stanima, this would make the game feel less monotonous I think.

I liked the retro sound and visuals, and I really liked the blood splatter freeze frame on game over.

Everything works perfectly. Visuals and sounds are awesome too, especially like how the rocks hit the machine. But I think there needs to be more things to make it more fun. I think giving the player more reaction time would be better, perhaps there could be rocks bouncing along the floor, also could be holes in the floor, maybe some higher obstacle so that you have to not jump