Also, there's no way this is only a 4 or 5 hour game unless the people who reviewed the game skipped a ton of cut-scenes or rushed through the game on easy mode. I put in about 4 hours (real time) into the game last night and I still have a good ways to go it seems like, unless the game very abruptly & out of nowhere rushes itself. Heck after my 4 hour sit down with it, my in-game timer still says I've only put in 2 hours of game time.
If the game is 4 or 5 hours of raw gameplay, not including cutscenes or codec conversations, I'm perfectly okay with that. If you skip all of the cutscenes in Metal Gear Solid 4, you can beat that game even faster.