Bullet heaven

An action game where you only steer your character, who attacks automatically, while ever-larger hordes of enemies close in. Levelling up offers a random choice of upgrades, and the challenge is combining them to survive until time runs out.

Also known as: Vampire Survivors-like, survivors-like, horde survival, reverse bullet hell

This is a basic entry: it has the definition and the classification. Full entries add history, games and a demo.