Games like Section 13
Games like Section 13 include The Last Stand: Aftermath, Yet Another Zombie Survivors, SYNTHETIK: Legion Rising, 20 Minutes Till Dawn, and SYNTHETIK 2. We matched them by the tags players give Section 13 on Steam (Dark, Top-Down Shooter, Action Roguelike, Twin Stick Shooter, and Zombies): closest matches first, and among equally close ones the better-known games.

The Last Stand: Aftermath
Shared: Top-Down Shooter · Zombies · Action Roguelike

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

SYNTHETIK: Legion Rising
Shared: Top-Down Shooter · Action Roguelike · Roguelite

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

SYNTHETIK 2
Shared: Top-Down Shooter · Action Roguelike · Roguelite

The Binding of Isaac
Shared: Action Roguelike · Dark · Indie

The Binding of Isaac: Rebirth
Shared: Action Roguelike · Dark · Indie

Hades
Shared: Action Roguelike · Roguelite · Indie

Risk of Rain 2
Shared: Action Roguelike · Roguelite · Shooter

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

Megabonk
Shared: Action Roguelike · Roguelite · Survival

Nuclear Throne
Shared: Action Roguelike · Top-Down Shooter · Roguelite

Relic Hunters Zero: Remix
Shared: Top-Down Shooter · Twin Stick Shooter · Action Roguelike

Brotato
Shared: Action Roguelike · Singleplayer · Roguelite

Enter the Gungeon
Shared: Action Roguelike · Twin Stick Shooter · Roguelike

Left 4 Dead 2
Shared: Zombies · Shooter · Survival

Zombieville USA 3D
Shared: Top-Down Shooter · Action Roguelike · Shooter

Blazing Beaks
Shared: Action Roguelike · Top-Down Shooter · Roguelite

Gunfire Reborn
Shared: Roguelite · Action Roguelike · Roguelike

Escape From Duckov
Shared: Top-Down Shooter · Adventure · Shooter

Voidigo
Shared: Action Roguelike · Twin Stick Shooter · Top-Down Shooter

Dead Cells
Shared: Action Roguelike · Adventure · Roguelite

Vampire Survivors
Shared: Action Roguelike · Roguelite · Singleplayer

Shape of Dreams
Shared: Action Roguelike · Roguelite · PvE