Games like Ludwig!
Games like Ludwig! include Broforce, Castle Crashers®, Cyberhunt, SANABI, and Pikuniku. We matched them by the tags players give Ludwig! on Steam (Action, Adventure, Shoot 'Em Up, Cute, and Wholesome): closest matches first, and among equally close ones the better-known games.

Broforce
Shared: Action · 2D · Local Co-Op

Castle Crashers®
Shared: 2D · Adventure · Action

Cyberhunt
Shared: Action · Adventure · Shoot 'Em Up

SANABI
Shared: Action · Adventure · Pixel Graphics

Pikuniku
Shared: Adventure · Cute · Action

Deaths Door
Shared: Cute · Action · Adventure

Gato Roboto
Shared: Action · Adventure · 2D

Shovel Knight: Treasure Trove
Shared: Adventure · Action · 2D

BOKURA
Shared: Adventure · Action · 2D

Rayman® Origins
Shared: Adventure · 2D · Action

PRAGMATA
Shared: Action · Cute · Adventure

Terraria
Shared: Adventure · 2D · Pixel Graphics

Skul: The Hero Slayer
Shared: Action · 2D · Pixel Graphics

Escape From Duckov
Shared: Action · Adventure · Cute

Rayman® Legends
Shared: Adventure · Action · Local Co-Op

Enter the Gungeon
Shared: Pixel Graphics · Local Co-Op · Action

Webbed
Shared: Cute · 2D · Pixel Graphics

Dungeon Munchies
Shared: Action · Adventure · Pixel Graphics

Huntdown
Shared: Action · Shoot 'Em Up · Local Co-Op

Cat Quest II
Shared: Adventure · Local Co-Op · Action

Dead Cells
Shared: Adventure · 2D · Pixel Graphics

Cuphead
Shared: Local Co-Op · 2D · Action

Revolution Ace
Shared: Action · Shoot 'Em Up · Local Co-Op

METAL SLUG
Shared: Action · Shoot 'Em Up · 2D