you can find a list of achievements at: http://www.xbox360achievements.org/game/call-of-duty-modern-warfare-2/achievements/
and also a guide for them at:http://www.xbox360achievements.org/game/call-of-duty-modern-warfare-2/guide/
Nothing happens other than getting the achievements and trophies in modern warfare 2. But in modern warfare 1, you get to unlock certain cheat codes that can be used during the game.
nothing you just get achievements but infinity ward said that they will do what they did on cod 4 modern warfare 1 and make cheats for when u collect them
Modern warfare reflex and modern warfare are the same. Modern warfare "reflex" means that its for wii. If its just modern warfare its for the other consoles
They do nothing besides earn achievements.
Modern warfare 2
modern warfare 2 is better .
Modern Warfare 2
Yes.
modern warfare 2
Call of Duty Modern Warfare 2
The intel items in Call of Duty: Modern Warfare 2 only unlocks trophies (PS3) or achievements (Xbox 360) when the player has collected 22 and 45 of the intel items. Unlike Call of Duty 4: Modern Warfare; collecting intel items do not unlock cheats for the single player campaign.
The related link lists and describes the 51 trophies for Call of Duty Modern Warfare 2 The 50 achievements for the Xbox 360 Game and the points earned are also included in the descriptions at the related link