Here is the full list of all 47 Titan Attacks achievements.
Destroyed 100 saucers
100 aliens escape capture
Killed 100 parachuting aliens
50 aliens escape capture
Completed the Titan levels
Perfect Challenge Level 98
25 aliens escape capture
Perfect Challenge Level 91
10 aliens escape capture
Perfect Challenge Level 84
Used 25 smartbombs
Captured 100 live aliens
Completed the Saturn levels
Perfect Challenge Level 77
Killed 50 parachuting aliens
Perfect Challenge Level 70
Perfect Challenge Level 63
Completed the Mars levels
Perfect Challenge Level 56
Captured 50 live aliens
Killed 25 parachuting aliens
Perfect Challenge Level 49
Perfect Challenge Level 42
Destroyed 50 saucers
Completed the Moon levels
Captured 25 live aliens
Perfect Challenge Level 28
Got 100 skill shots
Killed 10 parachuting aliens
Perfect Challenge Level 21
Perfect Challenge Level 14
Perfect Challenge Level 7
Guns and addons maxed
Everything maxed out
Upgraded addons to maximum rate
Maxed gun bullets
Maxed gun power
Added all addons to ship
Completed the Earth Levels
Got 50 skill shots
Perfect Challenge Level 35
Captured 10 live aliens
Destroyed 25 saucers
Got 25 skill shots
Got 10 skill shots
Got the x9 multiplier
Destroyed 10 saucers