Most improved sequels

[Marks]

I'm not saying the prequel were bad in ALL cases here (in fact some of them were great too), just that the sequel I name made good improvements

- Call of Duty 4 from CoD3
- Crash Bandicoot 2 from CB
- Assassin's Creed 2 from AC
- NHL 08 from NHL 07....also NHL 11 from NHL 10