Here is the full list of all 23 Downwell trophies - there are 5 bronze, 10 silver, 7 gold and 1 platinum.
Complete a level without killing any enemy.
Have more than 3000 gems.
Complete a level without landing.
Beat the third area (hard mode).
Beat the second area (hard mode).
Beat the first area (hard mode).
Beat the boss.
Complete a level without shooting.
Complete a level without visiting siderooms.
Land a 100 combo.
Beat the fourth area.
Beat the third area
Complete a level without taking damage.
Land a 30 combo.
Beat the second area.
Beat the first area.
Land a 10 combo.
Completed all other trophies.
Complete an area without taking damage.
Complete an area without landing.
Beat the fourth area (hard mode).
Beat the boss (hard mode).
Have more than 5000 gems.