Here is the full list of all 18 Citrus Rampage achievements.
Kill one player in any mode
Kill 50 players in any game mode
Kill 100 players in any game mode
Kill 500 players in any game mode
Score a goal in soccer mode
Score 50 goals in soccer mode
Score 100 goals in soccer mode
Score 500 goals in soccer mode
Finish your first match in any game mode
Finish 10 matches in any game mode
Finish 25 matches in any game mode
Finish 50 matches in any game mode
Equip Zombie Killer in any game mode
Equip the Metal Maker in any game mode
Equip the Sweetie in any game mode
Equip the HandGun in any game mode
Equip the Pie Pi gun in any game mode
Equip the Toasty in any game mode