Here is the full list of all 13 Alien Zombie Megadeath achievements.
Complete the introduction training level.
Unlock one of the extra Spacesuits.
Unlock 20 levels.
Get a combined total score of 3 million on all levels.
Unlock the UFO upgrade.
Unlock all the levels.
Score 2 million on any single level.
Unlock all of the extra Spacesuits.
Get a combined total score of 30 million on all levels.
Complete all the adventure levels. The blue ones!
Easy! Collect all the medals.
Get the multiplier to x5
Get the multiplier to x10