Time Shooter 3: SWAT is built on the Superhot idea and executes it well: time only advances when you move. Stand still and bullets hang in the air; step sideways and the room comes to life for exactly as long as you're moving.
That turns a shooter into a puzzle. Every room is a solvable problem — you can stand frozen and plan the exact order to take enemies in, then execute it in a few seconds of real time.
Time advances only while you move. Standing still freezes bullets mid-air, which turns each room into a puzzle you can solve at leisure and then execute.
The same central idea as Superhot, in a browser-playable SWAT setting.
Yes, though it's a 3D game — close other tabs on older hardware.