The Halo franchise is an odd one. The original trilogy was loved by the fans, be it for the hugely entertaining multiplayer content (Halo 2 is arguably the reason why Xbox Live initially succeeded) or
Accessible gameplay; but depth is there for veterans of RTS games; Story is great; for both fans and newcomers alike; Looks and sounds gorgeous; Blitz mode is a unique multiplayer addition; Skirmish modes against AI offer almost infinite replayability
Controls can still be an issue when things get hectic; Story sometimes feels like a setup for another game