Simplicity is king and queen!
This is another good example on how some simple shapes, a minimalistic UI and a small shader can be enough to make an easy to learn, hard to master game.
One critic point: The hit sound - when you hit a red square was quite loud compared to the movement sound, so I messed up my first round by just being surprised and having to turn down the volume ^^.
I can well imagine that you can insert some more things as time progresses in the future. Like a chain of red blocks running throught the screen from left to right, or some blocks, that just stop for a second before they move on. Even some powerups maybe or some bad things, like permanent obstacles appearing over time.
Good game!