Here is the full list of all 12 Tennis in the Face achievements.
Knock out six opponents with a single Explodz explosion.
Serve a ball that bounces 100 times.
Destroy three vending machines with a ball and a single serve.
Defeat the 10tons crew.
Collect three briefcases with a single serve.
Destroy 10 pieces of glass during one level.
Earn 1,000,000 points in the main menu.
Earn at least one extra ball from every level in the first district.
Knock out 5 enemies before the fourth bounce.
Score 25,000 points with a single serve.
Get five headshots with a single serve.
In a level with at least three enemies, knock everyone out with the first serve.