Every time I play just cause 2 I fail to get over how awesome it is. I never "got" the demo when it came out, either. I played a bit but didn't see its genius at the time, and also when I bought it it sat unplayed for ages. Now I'd say it's possibly the best game I've ever played for awesome graphics and pure fun. Not sure why I'm posting this in the steam thread, but it's always like 3 quid in every steam sale. There's a tenuous link for you!
I got it over the Steam summer sale and your post just made me finally give it a try...
I am surprised at how much it feels like Bionic Commando to me, maybe just the first tutorial part is so much like that? Grappling from one place to another...pretty fun to do so