I've got it myself, and it runs quite playably (although not quite as smooth as I'd like in some parts) with everything cranked up to max/ultra details, with no AA or anything.
I mean, <i>look</i> at the game. It's the first engine I've seen that can even begin to cope with some of the environments it puts you in, with such huge open spaces. It's the first game to <i>really</i> do sniping justice. frankly I'm amazed they could get something that looks this good running on todays hardware anyway.
<i>Plus</i>, it was playable on a Duron 1.4Ghz with 256Mb of RAM and a geforce 32Mb DDR card (yup, a geforce <b>1</b>!), with lower details, which tells me the engine is actually very scalable, and therefore quite well written really. granted it didn't look anything like as nice as the newer cards, but it still looked ok.
don't forget this is a next-gen engine that will be powering games for a few years. by the end of it's (the engine that is) lifetime your rig will be distinctly mid-range or maybe even low-mid range.
How many levels are there? I think I'm on level 5 or so... It's all been good fun so far. Best game I've played in a while.
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Epox 8RDA+ rev1.1 w/ Custom NB HS
XP1700+ @205x11 (~2.26Ghz), 1.575Vcore
2x256Mb Corsair PC3200LL 2-2-2-4
Sapphire 9800Pro 420/744