Playing this older version shows just how important the smallest of changes can be to vastly improve the quality of life of a game.
Case in point? Collision detection in this version. In Super Hexagon, you can move against walls to the side of you without issue, but here you don't have that luxury. You touch a wall from any angle, you lose.
And after getting used to Super Hexagon, this is borderline unplayable for me without that one little difference.