Games like Maniac
Games like Maniac include Vampire Survivors, Brotato, BALL x PIT, Megabonk, and Yet Another Zombie Survivors. We matched them by the tags players give Maniac on Steam (Singleplayer, Simulation, Action Roguelike, Top-Down Shooter, and Top-Down): closest matches first, and among equally close ones the better-known games.

Vampire Survivors
Shared: Action Roguelike · Bullet Hell · Singleplayer

Brotato
Shared: Singleplayer · Action Roguelike · Roguelike

BALL x PIT
Shared: Action Roguelike · Action · Bullet Hell

Megabonk
Shared: Action Roguelike · Roguelike · Bullet Hell

Yet Another Zombie Survivors
Shared: Action Roguelike · Top-Down Shooter · Singleplayer

Enter the Gungeon
Shared: Action Roguelike · Bullet Hell · Roguelike

Halls of Torment
Shared: Action Roguelike · Bullet Hell · Roguelike

Nuclear Throne
Shared: Action Roguelike · Roguelike · Bullet Hell

Deep Rock Galactic: Survivor
Shared: Action Roguelike · Top-Down Shooter · Bullet Hell

Hades
Shared: Action Roguelike · Singleplayer · Roguelike

Soulstone Survivors
Shared: Action Roguelike · Bullet Hell · Roguelike

鬼谷八荒 Tale of Immortal
Shared: Singleplayer · Simulation · Sandbox

Mount & Blade II: Bannerlord
Shared: Singleplayer · Open World · Simulation

The Binding of Isaac
Shared: Action Roguelike · Roguelike · Singleplayer

Tiny Rogues
Shared: Action Roguelike · Top-Down Shooter · Bullet Hell

Apocalypse Party
Shared: Singleplayer · Action Roguelike · Top-Down Shooter

Galactic Glitch
Shared: Action Roguelike · Top-Down Shooter · Singleplayer

Noita
Shared: Roguelike · Action Roguelike · Sandbox

Goat Simulator
Shared: Simulation · Sandbox · Open World

The Precinct
Shared: Singleplayer · Top-Down Shooter · Simulation

Magicraft
Shared: Action Roguelike · Bullet Hell · Roguelike

BeamNG.drive
Shared: Simulation · Singleplayer · Sandbox

Totally Accurate Battle Simulator
Shared: Simulation · Singleplayer · Sandbox

20 Minutes Till Dawn
Shared: Action Roguelike · Bullet Hell · Top-Down Shooter