This was actually the most fun I've had so far playing my queue. I felt like I could get to the highscore but then some dice hit me without noticing and I got back to the menu. I would have loved a more fleshed out world but what you offer works. 

I'm not gonna lie, I really liked the sound design and the way the dice fly around after you shoot them. However:

• The 'dead' dice still give you points if you shoot them;
• The shots 'kill' dice even after rebounding off a wall or the floor, maybe consider destroying them after they collide or at least making them non-deadly;
• I'd rebalance the mouse movement speed, player movement speed, gravity strength, and jump strength (mouse movement speed for example is too fast to be accurate);
• I'd make the dice spawn more often over time, eventually I got the hang of it and got bored because there was little challenge.

I agree the sensitivity was pretty high, but other than that it felt pretty slick. I did find you could shoot enemies you already defeated to accrue more points, I couldn't tell if this was intentional or not.