It's an emulator! That plays old LucasArts adventure games, along with a handful of other similar titles. You'll still need the actual disks/CD, of course. Unless you want to play Beneath a Steel Sky, because Revolution Software provided the source code. Oh, and Beneath a Steel Sky is available as a free download from the site. The emulator also supports Simon the Sorceror 1 & 2, Broken Sword, and Flight of the Amazon Queen, which is also freely available thanks to John Passfield and Steven Stamatiadis.
breaking news: I broke down and bought the Blue controller. I don't need it, I have 2 already, it's just blue, but I had a weird Target gift card and I'm silly. It's BLUE. (And then maybe I'll trade in one of the others to pay for Last of Us? A plan!)