Passwords, Memory Cards, split-screen multiplayer, unlockables instead of DLC, the Flight Sim genre (I miss you colony wars, rogue squadron, etc), Jrpgs that I could be convinced to play, sprite-based graphics, large party sizes in rpgs, reduced npc/party member plot immortality. Isometric camera games, increased complexity in game mechanics, lack of DLC, physical copies of computer games, lesser prevalence of DRM, increased moddibility of games. Long games. 2d-metroid games, infinity engine games, turn-based combat, less generic AAA games in general, Star Trek games, Star Wars games,and Forgotten Realms games that aren't MMOs, lack of level scaling (if I backtrack, I want to be able to stomp all over those Eye Goos/Orcs/Robots/etc, not fight level 50 versions of them!), cheat codes, secrets, and bonus bosses/challenge areas, non regenerating health/magic.
Probably a few things I have left out, because I *vastly* prefer older games. For examples, I would be vastly more interested if Bioware announced a new Infinity Engine game or if Capcom announced a new Breath of Fire for the PS1/PS2 than I am for *anything* either company is working on right now. Kinda a disappointing feeling knowing that once you are finished with your backlog, of older games, there really isn't much else to look forward to.