Here is the full list of all 20 Gravity Crash trophies - there are 19 bronze and 1 silver.
Gain a score of 1,048,576
Finish the single player campaign game
Find all gems in every level
Activate every node in the game, including those in secret levels
Collect all artifact pieces
Rescue 50 stranded crewmen
Collect a total of 10 purple gems across different levels
Kill 255 gun or missile turrets
Unlock any secret level
Have rear, side and 3-way fire simultaneously
Let a homing missile chase you until it runs out of fuel
Complete 'Vectora' level without firing a single shot
Beat the recommended time on 10 levels
Complete 'Norova' level without refuelling or dying
Defeat any boss
In manual shield mode, save yourself with only 5% of the shield remaining
Find 5 user created levels you like, and rate the creators
Refuel your ship after the fuel depleted warning message is displayed
Complete all training lessons
Create and publish a level then have it rated by 5 users