According to Bungie.net Halo Reach will have 49 achievements total. Twenty-three are campaign specific achievements. They have been seperated into different groups.These are the following: Campaign (23), Firefight (7), Multiplayer (4), Training (6) and Player Experience (9) Below is a list of achievement and how to obtain them. Enjoy!

• A Monument to All Your Sins – Complete each Campaign Mission on Legendary – alone.
• Banshees, Fast and Low – Hijack a Banshee during the Reach Campaign.
• Yes, Sensei – Earn a First Strike Medal in a Matchmaking game.
• A New Challenger – Complete all of the Daily Challenges in a given day.
• Make It Rain – Purchase an item from the Armory that requires the rank of Lt. Colonel.
• If They Came to Hear Me Beg – Perform an Assassination against an Elite to survive a fall that would’ve been fatal.

Source Bungie.net

Written by: William McDonald Writer