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).
Beat the first area (hard mode).
Beat the boss.
Complete an area without landing.
Complete an area without taking damage.
Land a 100 combo.
Beat the fourth area.
Have more than 5000 gems.
Beat the third area
Have more than 3000 gems.
Beat the second area.
Complete a level without landing.
Land a 30 combo.
Land a 10 combo.
Complete a level without killing any enemy.
Complete a level without taking damage.
Beat the first area.
Complete a level without shooting.
Complete a level without visiting siderooms.