Games like Space Battle - Mayhem
Games like Space Battle - Mayhem include Bloons TD 6, Plants vs. Zombies GOTY Edition, 20 Minutes Till Dawn, Minishoot' Adventures, and Kingdom Rush - Tower Defense. We matched them by the tags players give Space Battle - Mayhem on Steam (RPG, Strategy, Casual, Tower Defense, and Bullet Hell): closest matches first, and among equally close ones the better-known games.

Bloons TD 6
Shared: Strategy · Tower Defense · Casual

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

20 Minutes Till Dawn
Shared: Bullet Hell · Top-Down Shooter · Casual

Minishoot' Adventures
Shared: Bullet Hell · Twin Stick Shooter · RPG

Kingdom Rush - Tower Defense
Shared: Strategy · Tower Defense · Casual

Ninja Kiwi Archive
Shared: Casual · Strategy · Tower Defense

Vampire Survivors
Shared: Bullet Hell · Casual · Singleplayer

Kingdom Rush Origins - Tower Defense
Shared: Strategy · Tower Defense · Casual

Plebby Quest: The Crusades
Shared: Strategy · Casual · RPG

Mount & Blade II: Bannerlord
Shared: Strategy · RPG · Singleplayer

X-Morph: Defense
Shared: Strategy · Tower Defense · Twin Stick Shooter

The Scroll of Taiwu : Beyond The Dome
Shared: RPG · Strategy · Casual

Brotato
Shared: Bullet Hell · Singleplayer · RPG

Bloons TD 5
Shared: Strategy · Tower Defense · Casual

Bardbarian
Shared: Strategy · Tower Defense · RPG

Kingdom Rush Frontiers - Tower Defense
Shared: Strategy · Tower Defense · Casual

Goobies
Shared: Bullet Hell · Casual · Top-Down Shooter

Overdungeon
Shared: Strategy · RPG · Casual

Dungeon of the ENDLESS™
Shared: Strategy · Tower Defense · RPG

Orcs Must Die! 2
Shared: Tower Defense · Strategy · RPG

Apocalypse Party
Shared: Casual · Bullet Hell · Top-Down Shooter

Rock 'N' Roll Defense
Shared: Strategy · Tower Defense · Casual

XCOM 2
Shared: Strategy · RPG · Singleplayer