For me, gaming nowadays has begun to feel a lot more like a chore than something enjoyable. I attribute that to recent games being focused around their respective reward systems (Halo 5's REQ System, any number of FPS's with similar "pack" systems, Destiny's RNG, etc) as opposed to the activities done to unlock said rewards. I stopped playing Halo 5 regularly after I unlocked everything in the REQ system, with Customs and new Updates bringing me back once in awhile. I probably won't play Destiny until RoI comes out, simply because I've done everything I can do on my main (LITERALLY EVERYTHING). I stopped playing Just Cause 3 after I'd unlocked everything. And yet, there are still games that I've basically completed that I still go back to. Burnout Paradise, which is still my favorite game (if only it was BC), is a game I regularly revisit. Fall of Cybertron's Campaign is something I've replayed literally hundreds of times, and I will continue to due so. I've essentially "beat" both games (heck, this is my second save of Burnout Paradise), and yet unlike more recent games, they still keep me interested. Which brings me to my main point: a "good game" is a game that keeps you playing even after you've unlocked everything, beaten all the challenges, killed the final boss, etc. It keeps you playing not because of a goal or reward but because the gameplay is just so well done that the game can survive solely on that. Which is why I also think that games shouldn't have the seeming requirement of having Post-launch Updates or DLC to survive. The game you release should have all the stops pulled out, all the content and ideas you can manage to squeeze into that disc, all available at launch. DLC should be an afterthought, so to speak, a treat to the game's playerbase, something that isn't planned or advertised before the game even launches. And while that's simply not possible with a game like Destiny (which is due to the type of game it is, which I'm fine with), with a game like Halo 5, which I've tried so hard to like, the fact that it shipped with so few core features that even Halo 4 had (and I'm fine with them delaying Forge, because it was so worth it) really ruined 343i's reputation and utterly killed the already-dying Halo Machinima scene. In short, a good game is one that performs at its peak level of enjoyability regardless of how far you've progressed in it or how long it's been out or how many times it's been updated.