You're flying on a bathtub and pushing demons out of the sky. This is Joust — a game that didn't create a world to fit into, but built one around three simple ideas: fly, push, don't fall.

It's a platformer from 1983, originally released by Williams Electronics in arcade machines. It later appeared on computers in various versions, including the DOS version for PC. You play as a knight on a flying machine — it's more of a weird suspended contraption than a bathtub, but it invites imagination — and your task is to eliminate demons that emerge from the bottom of the screen. You catch them from above, knock them down, and they fall. If you fall, you end up in the abyss and lose a life.
The controls are solid. Arrow keys to fly, a button to flap — flapping your wings to stay alive. If you catch a demon from above, you flip it and collect it. You fight the same demons in different waves, gradually getting faster and smarter — we know this from demons in every arcade game of the eighties. Those few screens repeat, but it never felt wrong, because the physics of falling and pushing are so addictive that you're swimming in this sense of control and zip. Some waves are frustrating though — when there are too many demons and you can't get them all, you'll find yourself on the edge of the abyss. The game then keeps you at a pace that's no longer fun, but execution.
Joust became a classic not because it had the best graphics or depth — but because its core works. Pushing enemies, fall physics, the pull into the unknown. Later, it lived on in the memory of players who connected it to games like Lunar Lander or later to mechanics in Flappy Bird. A simple system, infinite potential.
Today it lasts about twenty minutes before all the combinations repeat and your brain says that anything further is just grinding. But those twenty minutes are worth it. If you enjoy addictive craft without story, without deeper goals, just pure control — Joust is for you. You've got it in an emulator in a second.