Games like Deadtime Defenders
Games like Deadtime Defenders include Warframe, Alien Shooter 2: Reloaded, The First Descendant, Crazy Flasher Series 2021, and Borderlands 2. We matched them by the tags players give Deadtime Defenders on Steam (Beat 'em up, Looter Shooter, Side Scroller, Shoot 'Em Up, and Collectathon): closest matches first, and among equally close ones the better-known games.

Warframe
Shared: Looter Shooter · Action RPG · RPG

Alien Shooter 2: Reloaded
Shared: Looter Shooter · Shoot 'Em Up · PvE

The First Descendant
Shared: Looter Shooter · Shooter · RPG

Crazy Flasher Series 2021
Shared: Beat 'em up · Side Scroller · Looter Shooter

Borderlands 2
Shared: Looter Shooter · Shooter · Action

Borderlands 4
Shared: Looter Shooter · PvE · Action RPG

Lost Castle
Shared: Beat 'em up · Side Scroller · PvE

Streets of Rage 4
Shared: Beat 'em up · Side Scroller · 2D

Escape from Tarkov
Shared: Looter Shooter · Shooter · Gun Customization

OUTRIDERS
Shared: Looter Shooter · RPG · Shooter

Tom Clancy’s The Division® 2
Shared: Looter Shooter · Shooter · RPG

Tiny Tina's Wonderlands
Shared: Looter Shooter · Shooter · RPG

Destiny 2
Shared: Looter Shooter · PvE · Shooter

PAYDAY 2
Shared: Looter Shooter · Shooter · Action

Relic Hunters Legend
Shared: Looter Shooter · Action RPG · Shooter

ASTLIBRA Revision
Shared: Side Scroller · Action RPG · 2D

MADNESS: Project Nexus
Shared: Beat 'em up · Shooter · Character Customization

Borderlands 3
Shared: Looter Shooter · RPG · Shooter

EVERSPACE™ 2
Shared: Looter Shooter · Shooter · Action RPG

Dungeon Fighter Online
Shared: Beat 'em up · Character Customization · RPG

Teenage Mutant Ninja Turtles: Shredder's Revenge
Shared: Beat 'em up · Side Scroller · 2D

Huntdown
Shared: Side Scroller · Shoot 'Em Up · Shooter

Alien Shooter 2 - The Legend
Shared: Looter Shooter · Shooter · Action RPG

The Forever Winter
Shared: Looter Shooter · PvE · Shooter