When I was learning to drive many summers ago (back when summer vacations were still a thing) my Mum would take me out during the day to practice. I'd do the driving, she'd do the being-worried-about-our-mortality and navigation. At some point on every trip, without fail, she would instruct me to take a right turn and upon complying she would yell "No not that right! Your other right!"
Playing Super Hexagon is a bit like that, except it all happens in your head.
It's a deceptively simple concept: navigate a hexagon shaped maze, turning left or right to dodge incoming walls. In practice, Super Hexagon is like running head-first into an oncoming train with the aid of hallucinogens. It's a game that requires quick decisions while your perspective pulsates, tumbles, and generally serves to confuse. At some point you'll question your understanding of clockwise and counterclockwise.
Initially, you won't last more than a few seconds. With a little experience that number will tick up to ten, maybe twenty, seconds. Super Hexagon makes no apologies about it's difficulty, but losing always feels fair. It's easy to convince yourself that you just made a silly, avoidable mistake, so you keep trying. With practice, which involves memorizing recurring segments of the randomized mazes in addition to improvising and reacting to immediate dangers, you'll get better.
If you're really dedicated you might progress past the one minute mark and unlock a new mode. At this point you might feel pretty smug, even like you're good at Super Hexagon. Instead, trying a harder mode will feel like a whole new impenetrable game. It will demand you react faster, perform more precisely, and most importantly, gain a deeper understanding of Super Hexagon.
And therein lies the appeal: the ability to deeply explore a game system, peeling back the hexagon-shaped layers one by one to gain an appreciation and (eventually) mastery over Super Hexagon itself.