I personally found the controls to be a bit hard to remember. (Maybe put them below in the order of the keys [BLUE-RED-YELLOW] ?) Also, in the Game Overview it's generally a bad idea to say stuff like "durr" and "like you didn't know that," this may anger the player if they actually didn't know that. WASD is just about as popular as the arrow keys now a days so maybe add that in as well, just put this code under the create event:
keyboard_set_map(ord('A'),vk_left)
keyboard_set_map(ord('D'),vk_right)
That's all I have to say! Hope you learn something from this comment!