Games like Defense Duel
Games like Defense Duel include Bloons TD 6, Thronefall, Creeper World 4, Kingdom Rush - Tower Defense, and Plants vs. Zombies GOTY Edition. We matched them by the tags players give Defense Duel on Steam (Real Time Tactics, Auto Battler, Tower Defense, Arcade, and Strategy): closest matches first, and among equally close ones the better-known games.

Bloons TD 6
Shared: Tower Defense · Strategy · 3D

Thronefall
Shared: Tower Defense · Strategy · 3D

Creeper World 4
Shared: Real Time Tactics · Tower Defense · Strategy

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

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

Legion TD 2 - Multiplayer Tower Defense
Shared: Tower Defense · Auto Battler · Strategy

Northend Tower Defense
Shared: Tower Defense · Auto Battler · Strategy

Warpips
Shared: Tower Defense · Auto Battler · Strategy

GemCraft - Chasing Shadows
Shared: Tower Defense · Strategy · Indie

Minimalist Tower Defense
Shared: Real Time Tactics · Tower Defense · Strategy

Children of the Sun
Shared: Real Time Tactics · Arcade · Strategy

Taur
Shared: Tower Defense · Strategy · Indie

Aliens: Dark Descent
Shared: Real Time Tactics · Strategy · Action

Bad North: Jotunn Edition
Shared: Real Time Tactics · Tower Defense · Auto Battler

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

Shadow Tactics: Blades of the Shogun
Shared: Real Time Tactics · Strategy · Indie

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

Door Kickers 2: Task Force North
Shared: Real Time Tactics · Top-Down · Strategy

Door Kickers
Shared: Strategy · Indie · Top-Down

Artisan TD
Shared: Tower Defense · Strategy · Real Time Tactics

Rogue Tower
Shared: Tower Defense · Strategy · 3D

Infested Planet
Shared: Tower Defense · Strategy · Indie

Heretic's Fork
Shared: Tower Defense · Strategy · Arcade

Bloons TD 5
Shared: Tower Defense · Strategy · Casual