Games like Protect the Planet
Games like Protect the Planet include FTL: Faster Than Light, Defy Gravity Extended, Zup! S, Game Dev Tycoon, and Vampire Survivors. We matched them by the tags players give Protect the Planet on Steam (Casual, Shooter, Typing, 2D, and Aliens): closest matches first, and among equally close ones the better-known games.

FTL: Faster Than Light
Shared: Space · Indie · Perma Death

Defy Gravity Extended
Shared: 2D · Space · Indie

Zup! S
Shared: Casual · 2D · Indie

Game Dev Tycoon
Shared: Casual · Indie · 2D

Vampire Survivors
Shared: 2D · Casual · Indie

ShellShock Live
Shared: 2D · Shooter · Casual

STAR WARS™ Battlefront™ II
Shared: Shooter · Space · Singleplayer

Melvor Idle
Shared: Casual · 2D · Indie

Plants vs. Zombies GOTY Edition
Shared: Casual · 2D · Singleplayer

Solar 2
Shared: Casual · Space · Indie

Timberman
Shared: Casual · 2D · Indie

To The Core
Shared: Casual · 2D · Indie

Among Us
Shared: 2D · Space · Casual

Bit Blaster XL
Shared: Shooter · 2D · Casual

BEEP
Shared: 2D · Indie · Casual

Cat Goes Fishing
Shared: 2D · Casual · Indie

A Dance of Fire and Ice
Shared: 2D · Indie · Singleplayer

Zup! 2
Shared: Casual · 2D · Indie

Planes, Bullets and Vodka
Shared: Casual · Shooter · 2D

Mountain
Shared: Casual · Indie · Singleplayer

Zup!
Shared: Casual · 2D · Indie

1000 days to escape
Shared: Casual · Space · Indie

Cosmoteer: Starship Architect & Commander
Shared: 2D · Space · Singleplayer

Zup! F
Shared: Casual · 2D · Indie