DoDonPachi

CAVE's 1997 release is one of the games that gave a whole sub-genre its name. Built by people who had previously worked on shooters at Toaplan, DoDonPachi pushed the idea of a shooter drowning the screen in enemy fire to a form that became the reference point for everything after it. Hundreds of slow projectiles fill the display in geometric patterns, and you slip between them because the hit detection covers only a tiny point at the centre of your ship. That is the key to the entire genre: the aim is not to dodge everything but to read patterns and find the gaps that were always there. Its second pillar is a scoring system built on chaining, where continuous fire maintains a combo across whole stages, turning play for points into a separate discipline with its own rules and tactics. The game ran on hardware capable of moving vast numbers of sprites simultaneously, which was the technical precondition for the genre existing at all. Visually it is dense 2D work with explosions that swallow the screen and a soundtrack that keeps the pressure on. Difficulty is severe even by arcade standards, and the second half has a reputation as some of the hardest content produced in that era without dedicated study. The opening stage, though, is surprisingly approachable for a newcomer. You can run it in the browser on OldGame.cz and decide within a single credit whether this pace suits you.