Game replayability.

[retrolinkx]

I like replaying games that I haven't played in a while, or to test my ability.

For example, I played Fallout 3 last summer because I loved it so much and wanted to play a different style.

I also played Halo 2 again for the Legendary, I stopped halfway because I want to see if I can beat it.

I usually replay games for the achievements, like in Halo Reach, I finished the Normal Campaign, then finished the Legendary a week later.

Metal Gear Solid 4 on the other hand is annoying to play to get the trophy's because I finished it 2 months ago, and it's still fresh in my head, so I don't really want to go through all of it again.