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