On a room with about 50 bad fluffies on it I'm getting about 13fps, untill I play some more and get off this room I can't get a better average.
The responsiveness is still quite playable, I'm comparing it to the mighty DROD games so its probably a bit unfair (even DROD crashed a few times on my system). Like I said its still much better than the double movements.
It would appear that the game doesn't use any hardware help and is all software rendered, maybe even without using DirectX (otherwise I would expect a much higher fps like what I get in other games).
I have played quite a few rooms now and haven't experienced any double movements, so it must have been one of my optional settings. So I'm thankful for help in that area anyhow.