Games like Slug's Sister Defense
Games like Slug's Sister Defense include Plants vs. Zombies GOTY Edition, Vampire Survivors, Donut County, Bloons TD 6, and Florence. We matched them by the tags players give Slug's Sister Defense on Steam (Casual, Indie, Early Access, Tower Defense, and Action Roguelike): closest matches first, and among equally close ones the better-known games.

Plants vs. Zombies GOTY Edition
Shared: Tower Defense · Casual · Singleplayer

Vampire Survivors
Shared: Action Roguelike · Indie · Casual

Donut County
Shared: Casual · Indie · Cute

Bloons TD 6
Shared: Tower Defense · Casual · Singleplayer

Florence
Shared: Casual · Indie · Cute

Little Inferno
Shared: Casual · Indie · Singleplayer

Unpacking
Shared: Casual · Cute · Indie

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

World of Goo
Shared: Indie · Casual · Singleplayer

Say No! More
Shared: Indie · Casual · Comedy

Gensokyo Night Festival
Shared: Indie · Casual · Early Access

Montaro
Shared: Casual · Indie · Cute

There's Poop In My Soup
Shared: Casual · Indie · Comedy

Megabonk
Shared: Indie · Action Roguelike · Singleplayer

WEBFISHING
Shared: Casual · Indie · Cute

Hades
Shared: Indie · Action Roguelike · Singleplayer

Pikuniku
Shared: Indie · Casual · Cute

Zup! S
Shared: Casual · Indie · Singleplayer

Bardbarian
Shared: Indie · Casual · Tower Defense

Slime Rancher
Shared: Cute · Singleplayer · Casual

LEGO® Builder's Journey
Shared: Indie · Casual · Cute

Assemble with Care
Shared: Casual · Indie · Singleplayer

Haunt the House: Terrortown
Shared: Indie · Casual · Cute

There Is No Game: Wrong Dimension
Shared: Indie · Casual · Comedy