Registered just to add my 10p to this pile - I've got a ticket open on this with UPlay too but I don't really expect a meaningful reply from them
've basically said if they can't fix it, I expect a refund tho!)
AMD 245 (Dual Core 2.9Ghz), 4 GB RAM, 5670 (512Mb GDDR5) Windows 7 64bit Desktop Res 1920x1080
Biggest issue is choppy framerate - it runs at 60fps about 75% of the time but certain places/events cause this to drop sharply - perhaps even into the 20s and 30s - and the game becomes like riding in treacle.
As someone else said, the newer outdoor levels are worse than the Warehouse ones, but it happens in both to some extent.
I've tested the game on a wide range of settings - but even on min settings at 1280x720 (the resolution I suspect the game is upscaling from - lazy lazy!) you still get fps drops in the worst places. I find it hard to believe that any degree of testing didn't spot this...
Worse still, I suspect these drops affect your score/times because levels I couldn't beat on higher graphical settings got easier as I scaled-back and got better framerates (e.g. the clock isn't locked to the framerate!?) - that means the game is MUCH harder for some people than others!?!?
Texture loading problems are limited to level starting areas for me - nowhere near as bad as some people's screenshots suggest their issues are but still quite nasty.
p.s. could we PLEASE have a shadows OFF option, it's likely shadows are part of the problem and shadows on Low are ugly-as-hell anyway so we may as well just lose them.