Isn't that the one where, instead of subcirbing, you pay money to be able to upload textures and the like, and to have spendable currency in-game?

Also, my contribution: I'd say that Half-Life was almost a deep-game, if you could do more interacting and wandering instead of being in a puzzle or between puzzles. But there've been 3 games that take you through it, plus some outstanding MODs that cover even more Black Mesa territory. Heck, the first 8 minutes of HL, where you can't so much as leave the tram car you're in, suggests a bigger world than many games before it ever encompassed.