This game feels nostalgic, you legit unlocked a memory of mine ahah
Overall your game is awesome, I enjoyed taking my time going through each puzzle.
There are a few things that you could improve to take your game to the next level. Having levels where you introduce each button separately would be cool, and then slowly you could add them together like you did to create some interesting challenges. Using the right click to remove a button was fine but I was expecting the left click to do that.
Amazing job with your game, keep it up!