Games like Astro Wars
Games like Astro Wars include Oxygen Not Included, RimWorld, Once Human, Prison Architect, and Drill Core. We matched them by the tags players give Astro Wars on Steam (Strategy, Massively Multiplayer, Colony Sim, Exploration, and 2D): closest matches first, and among equally close ones the better-known games.

Oxygen Not Included
Shared: Colony Sim · Base Building · 2D

RimWorld
Shared: Colony Sim · Strategy · Base Building

Once Human
Shared: Free to Play · Exploration · Strategy

Prison Architect
Shared: Strategy · Colony Sim · Base Building

Drill Core
Shared: Strategy · Colony Sim · Exploration

BidKing
Shared: Strategy · Massively Multiplayer · Exploration

They Are Billions
Shared: Strategy · Colony Sim · Base Building

Dwarf Fortress
Shared: Colony Sim · Strategy · Base Building

Going Medieval
Shared: Strategy · Colony Sim · Base Building

Space Haven
Shared: Colony Sim · Strategy · Base Building

Rise to Ruins
Shared: Colony Sim · Strategy · Base Building

Foxhole
Shared: Massively Multiplayer · Base Building · Strategy

Ratopia
Shared: Colony Sim · Strategy · Base Building

IXION
Shared: Strategy · Colony Sim · Base Building

60 Seconds! Reatomized
Shared: Strategy · 2D · Exploration

Cult of the Lamb
Shared: Base Building · Colony Sim · Strategy

ShellShock Live
Shared: Strategy · 2D · Massively Multiplayer

SPORE™
Shared: Colony Sim · Exploration · Strategy

Banished
Shared: Strategy · Colony Sim · Indie

Kingdoms and Castles
Shared: Colony Sim · Strategy · Base Building

SMITE®
Shared: Strategy · Free to Play · Massively Multiplayer

Kingdom Eighties
Shared: Exploration · Colony Sim · Strategy

Settlement Survival
Shared: Colony Sim · Strategy · Exploration

Rusted Warfare - RTS
Shared: Strategy · Base Building · 2D