That's the opposite for me, I can go back to a good SP game but I can't stand playing the same MP game for more than a few hours per year.

Multiplayer is not pinnacle of gaming.

Especially when the multiplayer experience is horrific - over caffeinated youth screaming slurs of all kinds as they bunnyhop around a supposed stealth map.

If the principle mechanic is 'you move, time moves' that would be a pretty difficult game. Lining up to slice a bullet your friend runs into the room, you die.

At $14 (~£8.50), that's what I expect from a game at that price level. It's a very interesting puzzle game, implementing a unique(-ish) mechanic; compare it to Portal or Antichamber, not an FPS.

If either player moves, the game moves -- players must coordinate

This would be amazing team play. It's bringing back memories of when I played in a top Quake clan when I was a teenager. You could practice and coordinate certain runs, some members sacrificing themselves to capture the flag - however with this the level of complexity and timing actually sounds fun and challenging enough that I'd be interested in starting to game again.

In this particular game, that would make things significantly easier. One player stands still while everyone else gets into position.

What if the time movement was in a local area of effect, and when multiple players had overlapping areas, there was a multiplier effect? That'd be cool.