Here is the full list of all 19 War in a Box: Paper Tanks achievements.
Win 10 rounds in a row
Finish the game in Expert mode
Collect 65 stars
Collect 50 stars
Built 20 TESLAS
Built 100 CANNONS
Destroy 300 units using HEAVY-GUN
Built 25 ARTILLERY
Destroy 1000 units using FLACK
Collect 35 stars
Lose 3 rounds in a row
Destroy 300 units using ARTILLERY
Built 25 FLACKS
Built 25 HEAVY-GUNS
Destroy 1000 units using CANNON
Destroy 50 units using TESLA
Finish the level with 1 life
Kill heavy tank or zeppelin with HEAVY-GUN
Granted for first kill