Intense. Fun. Too bad I felt like I was going to puke after 20 minutes. Others experienced the same thing. It’s happened to me in another game too: the water-skimmer chapter of Half Life 2. Maybe I’m getting too old for these types of games.
Still, good deal for a $1 game. The non-HD version plays better on the iPhone 3GS and still looks quite good. Downloads faster too, but at 537MB, it’s going to take awhile.
(I’d personally like to see Carmack return to the Commander Keen 2D side-scroller games of yore.)