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