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