01: save anywhere - yes
02: rewind button - um, like for cutscenes? or like braid where it's like "whoops, you went wrong? not anymore!"? For cutscenes I can understand. As a gameplay mechanic, no.
03: instant replay - um
04: avatar awards - complete this game in five minutes without dying? have a FAKE SHIRT.
05: splitscreen co-op (if the game has online co-op) - sure
06: language/gore filter - "No. This is the most stupid idea I've ever heard. If you don't want those in your games, play a different fucking game."
07: manuals - i fucking love manuals
08: skippable cutscenes - "yes, but only if they do it well; as in, press start to pause, then select "skip" from the menu"
09: rewatchable cutscenes - CINEMA MODE
10: achievement trackers (ala saints row 3, gears of war 2, l.a. noire, etc.) - sure
11: multiple difficulty levels - only two: NORMAL and SUPER NORMAL
12: good credits (playable scene behind it; epilogues; funny whatevers) - why not
13: "PREVIOUSLY ON" (sequels that give you a rundown of the last game) - or you could just play the last fucking game
14: cheat codes - if it adds something, and doesn't encourage you to not bother with the game. disable achievements and saving when cheats are used, for example.
15: new game+ - new game+ is my life