Experiencing the same problem on my 660. If the game isn't supported then I'm SOL for now (which is fine) but the graphics look doable and the gameplay runs fine for me. Or rather, it did yesterday. As of this morning the game seems to crash randomly instead of running stable
UPDATE: it seems like the zipline specifically is what's causing my game to crash right now. Otherwise it's completely functional just with borked graphics.
Intel(R) Core(TM) i7-4770 CPU @ 3.40GHz , 3401 Mhz, 4 Core(s)
NVIDIA GeForce GTX660
32 GB RAM