Blutsaugher - The first unlock, coming after 1/3rd of the achievements have been obtained, will replace the syringe gun. The gun will have a 0% chance to critical hit an enemy but will draw health with each successful hit.
Critzcrieg - This second unlock comes after the player has earned 2/3rds of the new achievements. This is the weapon that replaces the ubercharge's invulnerable period, opting to give the Medic's target a 100% chance for critical hits for a period of time.
Ubersaw - The final weapon comes only when all 36 achievements have been earned. This weapon, when it successfully connects with an enemy, will fill up the ubercharge up by 1/4th of its total. Four successful hits will completely fill up the Medic's ubercharge.