Here is the full list of all 20 NFL Blitz achievements worth 200 gamerscore. It takes around 30-35 hours to unlock all of the achievements on Xbox 360.
Purchase all Ultimate Players
Purchase all Ultimate Power Ups
Purchase all Pro Players
Trigger every power up
Enter 10 unique cheats in one Play Now or Blitz Gauntlet game by one user
Beat the Head to Head National Elite Battle Board
Get into the Head to Head Regional Elite Battle Board
Knock down a player with the Ninja fantasy character's jump kick hurdle
Ride the back of an on fire WR with the zombie fantasy character
Win a Risk and Reward game
Double pass for a touchdown
Do a celebration dance in your own endzone and get tackled for a safety
Catch on fire three times during a single game
Beat the National Elite Battle Board using a Blitz Team
Break three tackles in a row
Get your Blitz Team into the Regional Elite Battle Board
Get your Blitz Team into the Local Elite Battle Board
Recover an on-side kick
Get into the Head to Head Local Elite Battle Board
Unlock all Fantasy Characters (Lead profile only)