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