Here is the full list of all 14 RGB Rush achievements.
Play 100 games in total
Unlock the HEX gamemode
Guess a colour exactly (HEX single not included)
Play hex single in blind and timed mode
Attempt to press the enter button after the timer has ended
Exit a game without scoring any points
Actually tried the tutorial
Move a slider while holding spacebar to adjust all sliders at once. I'm proud of you for paying attention in the tutorial.
Score a point by typing a colour in correctly
Type in a number that's too large
Used the arrow keys to set a slider precisely
Make a guess with 0% accuracy
Press enter before you've even chosen a colour
Press exit to menu, but then don't press confirm because you want to keep playing