Here is the full list of all 33 Cannon Arena achievements.
Win 1 match
Win 10 matches
Win 50 matches
Unlock Dover
Unlock Giza
Unlock Alcatraz
Unlock Moon
Unlock Buffalo
Unlock Matera
Unlock Praga
Join 1 multiplayer match
Join 10 multiplayer matches
Join 50 multiplayer matches
Destroy 1000 buildings
Destroy 2000 buildings
Destroy 5000 buildings
Travel a total of 50 km
Travel a total of 100 km
Reach 2 lev unlock Molz and Dillox
Reach 3 lev unlock Mitarus
Stay unbeaten for 5 match
Stay unbeaten for 10 match
Finish singleplayer mode
Shoot 2500 shots
Shoot 5000 shots
Shoot 10000 shots
Ends a match without damaged buildings
Ends a match without suffering damage to the tank
Repairs the tank 250 times
Repairs the tank 500 times
Repairs the tank 1000 times
Hit enemy at least 5 times in a match
Hit enemy at least 15 times in a match