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