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