I have to say, what I want from a game has changed dramatically as I've gotten older. As a kid, there just weren't that many games around, and each one was a treasure. A new video game was a huge deal. So I wanted it to last. The more content, the better. I hadn't learned to hate grinding yet, and my young autistic mind actually enjoyed the repetitive tasks. And what were the alternatives? Going outside? There was dirt and bugs out there. I certainly spent plenty of time reading and watching TV and drawing and whatnot, but there weren't a whole lot of things demanding my attention back then.
Now I'm a full-fledged grown-up with my own apartment, two demanding jobs, a large group of friends (not one of whom is a gamer and many of whom are artists and musicians who often invite me to shows), a slew of health issues to deal with, and a constant battle with the Czech government for the right to live in their country. I'm also trying to finish writing several books, read at least a book a week, keep up with practicing drawing and painting, and the list goes on. I still love games, but I just do not have the time.
And on top of that, there are just so many games out there now. I've got 136 games in my Steam library, a couple dozen on Desura, I don't know how many DRM-free, and I don't even want to think about how many are untouched in my bundle libraries. When a game boasts 100+ hours of gameplay now, I don't even want to look at it. I don't have that many hours! And I no longer enjoy mind-numbingly tedious grind the way I did as a kid. So the loads of hours of gameplay are not even fun.
The games I play most often are the ones I can either finish fairly quickly, delete, and move on from, or ones without any sort of "end" that I can just stop playing whenever I feel like it and not feel like I'm missing out on something or wasting the game purchase. If you want to sell me a game, make it fairly short and sell it at a low price. That's what gets my attention now. Cut out all the boring crap and just give me the good stuff without filler.
The other big one that drives me crazy is any kind of "realistic" graphics. First of all, I get motion sickness from shooter-style games (I guess they call it "simulation sickness"), so I avoid 3d games almost universally. On top of that, they keep trying to make graphics look more realistic, which only results in making them less convincing. It's the "uncanny valley" thing. So I much prefer "retro" style (and I agree with whoever said that "retro" is not really the right word - it's just a different style, not an old one) and 2d graphics, and highly stylized imagery. The less they try to make it look real, the more immersive it is.