Lose your first game.

Defeat an enemy for the first time.

Gain a skill for the first time.

Increase the crew to two.

Increase the crew to five.

Kill 50 of them with the increased damage of the bullets.

Shoot 100 bullets while the rate of fire is increased.

Shoot 200 bullets while the rate of fire is increased.

Kill two or more enemies at once with a single laser shot.

Clear your first wave.

Reach the 3rd wave.

Reach the 6th wave.

Reach the 9th wave.

Reach the 12th wave.

Endure 3 waves with 1 piece of baumkuchen remaining.

Reach the 14th wave.

Reach the 16th wave.

Reach the 18th wave.

Reach the 19th wave.

Reach the 20th wave.

Reach the 5th wave.

Reach the 7th wave.

Reach the 10th wave.

Reach the 13th wave.

Reach the 17th wave.