I can only assume that he actually means "we have less competition on Linux", because my experience with Windows 8 as a gamer has been pretty damn good. Everything gaming-related works just as well as Win7, as far as I can tell. The games available on the app store are alright, but I don't see it competing with Steam when it comes to the high-powered AAA titles.
Edit: From another comment, it sounds like this is a bad quote, and that the Valve guy said nothing of the sort. Sorry to Valve for what I wrote previously, and shame on UbuntuVibes...
I don't own Crysis 2 to test, sorry. The only program that I had installed that flat-out broke due to the upgrade was actually Media Player Classic Home Cinema, which works fine now after updating to the latest version.
Edit: To expand a little bit on that, I've been a Windows user since the 3.1 days. I've done most (if not all) of the upgrades during that time frame at some point, and there are always programs that break. Games tend to be particularly fragile in this respect, possibly due to relying on undocumented/unsupported behavior to squeeze out extra performance.
Win98->XP (ME? what's that?) and XP->Vista were both particularly bad for games, as I think anyone old enough to be a PC gamer during those times remembers. However, it wasn't because XP or Vista weren't 'viable' for gaming - the games just needed patches to adjust to new OS behavior or remove reliance on deprecated APIs. Win7->Win8 is more comparable to Vista->Win7, judging by my experience so far. There are things that will break and certain games will need patches, but it won't be anything like the days of needing "Vista patches" for 90% of your games.
I haven't had many problems running games on Windows Vista/7, but the times I did have problems were extremely time consuming. I'm talking in the range of 10+ hours. Bioshock 2, for example, was plagued with the Games for Windows Live, which itself would only work with particular .NET runtimes you had to find yourself, plus very subtle sound driver configurations that had to be made (and I still can't get the game to run through Steam). 99% of games work out of the box, as expected. That 1%, though, is quite a headache.
Edit: From another comment, it sounds like this is a bad quote, and that the Valve guy said nothing of the sort. Sorry to Valve for what I wrote previously, and shame on UbuntuVibes...