You are the hourglass. Your sand is your health, your ammo, and the clock.

Time doesn't run on a timer — it runs at the speed your sand flows. Burn it fast and the whole world speeds up. Let it stall and everything stops, you included. 

What's coming for you is Procrastination, and the only thing you can shoot it with is your own time. Every shot spends some — but the grains land on the ground, and you can vacuum them back up with your other arm. Getting hit spills more of it.

When you run dry you flip yourself. Flips come from monoliths — guarded pillars you have to break to get the token they drop.

 Kill things, level up, spend points in the upgrade tree.