Free games like Planets Under Attack
Below are 8 free-to-play Steam games similar to Planets Under Attack, ranked by player overlap and content similarity. No purchase or Steam login required to view the list. Every pick is a full free-to-play title — not a demo, trial, or time-limited giveaway. imho.run's catalogue refreshes daily, so newly free or newly popular titles surface here without manual editing.
Want the full alternatives list (paid + free + Steam Deck + cheaper picks)? See the parent games like Planets Under Attack page.
Ranked picks
- 1
The Lab
Free-to-play alternative to Planets Under Attack — no purchase or trial window.
Welcome to The Lab, a compilation of Valve’s room-scale VR experiments set in a pocket universe within Aperture Science. Fix a robot, defend a castle, adopt a mechanical dog, and more. Still not sold? It’s free!
- 2
SCP: Secret Laboratory
Free-to-play alternative to Planets Under Attack — no purchase or trial window. Shares Indie with Planets Under Attack.
Deep within a secure underground facility, a sudden containment breach allows many of the secured anomalies to escape from their chambers. Assist the Foundation in re-securing the facility, help the Insurgency in their goal to capture it, or wreak havoc as an SCP in a frantic bid to escape.
- 3
Splitgate
Free-to-play alternative to Planets Under Attack — no purchase or trial window. Shares Indie with Planets Under Attack.
Splitgate is a free-to-play, fast-paced multiplayer shooter that features player-controlled portals. This sci-fi shooter takes the FPS genre to a new dimension with its portal mechanics, delivering high-flying, multi-dimensional combat.
- 4
Crusader Kings II
Free-to-play alternative to Planets Under Attack — no purchase or trial window. Shares Strategy with Planets Under Attack.
Explore one of the defining periods in world history in an experience crafted by the masters of Grand Strategy.
- 5
PlanetSide 2
Free-to-play alternative to Planets Under Attack — no purchase or trial window.
PlanetSide 2 is an all-out planetary war, where thousands of players battle as one across enormous continents. Utilize infantry, ground and air vehicles, and teamwork to destroy your enemies in this revolutionary first-person shooter on a massive scale.
- 6
Clicker Heroes
Free-to-play alternative to Planets Under Attack — no purchase or trial window. Shares Strategy and Indie with Planets Under Attack.
Click your way through hordes of monsters, earn gold, and recruit quirky heroes with powerful skills. Progress even while you're idle, and watch the numbers climb into the absurd. It’s a never-ending journey of clicks, crits, and colossal damage.
- 7
Minion Masters
Free-to-play alternative to Planets Under Attack — no purchase or trial window. Shares Strategy and Indie with Planets Under Attack.
An addictive fast-paced hybrid of Card games & Tower-Defense. Play 1v1 - or bring a friend for 2v2 - and engage in epic online multiplayer battles full of innovative strategy and awesome plays! Collect 200+ cards with unique mechanics, all free!
- 8
Bloons TD Battles
Free-to-play alternative to Planets Under Attack — no purchase or trial window. Shares Strategy with Planets Under Attack.
Go head to head with other players in a Bloon-popping battle for victory. From the creators of best-selling Bloons TD 5, this all new Battles game is specially designed for multiplayer combat, featuring the ability to control bloons directly and send them charging past your opponent's defenses.