Here is the full list of all 20 Gravity Crash Ultra trophies - there are 19 bronze and 1 silver.
Defeat any boss
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
Kill 255 gun or missile turrets
Rescue 50 stranded crewmen
Complete 'Norova' level without refuelling or dying
Complete 'Vectora' level without firing a single shot
Let a homing missile chase you until it runs out of fuel
Unlock any secret level
Activate every node in the game, including those in secret levels
Collect a total of 10 purple gems across different levels
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
Finish the single player campaign game