Halo 3: ODST is not what it was hyped up to be, consider it an expansion.
THE BAD:
- Repetitive missions
- Nearly the same as Halo 3, except that you are an ODST in campaign.
- Sort of easy (although some areas can be challenging)
- Nothing new, just the same stuff. - Gets boring after awhile.
THE GOOD:
- Firefight, an all new mode, that puts you in the position to fight off hordes of Covenant.
- A sort of good storyline
- Good cinematic scenes
- Keeps you interested for awhile...
- Online is still the same but since it has many people to play with it, it's what keeps the game alive.