Choose Planetary Zigma
Choose Planetary Zigma if you want an Indie and Free To Play experience. On Steam, it's free to play, so the barrier to trying it is zero.
Planetary Zigma vs Monster Mercs
Planetary Zigma and Monster Mercs both land in Action on Steam, which is why they keep getting compared. The comparison below is built from each game's Steam metadata — release year, genres, categories, Steam Deck status, price, and review score — refreshed daily by imho.run's scraper. Headline differences: Both are Action games on Steam. Planetary Zigma is free; Monster Mercs is paid (Price unknown). Both support cooperative play. No login or purchase needed — scroll for the full table, the verdict FAQ, and links to ranked similar games for both titles.
Which should you pick?
Choose Monster Mercs
Choose Monster Mercs if you want a RPG experience.
Both Planetary Zigma and Monster Mercs sit in Action on Steam and both list Multi-player, Online Co-op, and Co-op, so either pick lands in the same broad neighborhood. Use the side-by-side table for the feature view, or follow the "Games like" links below to see ranked alternatives for either title.
Side-by-side comparison
 Planetary Zigma |  Monster Mercs | |
|---|---|---|
| Released | — | — |
| Genres | Action, Indie, Free To Play | Action, RPG |
| Platforms | Windows, Linux | Windows, Linux |
| Steam Deck | Unrated | Unrated |
| Price | Free to play | Price unknown |
| Steam reviews | — | — |
| Multiplayer | Multi-player, Online Co-op, Co-op | Multi-player, Online Co-op, Co-op |
| Developers | LucasDevelops, HaraldWik | Izak Games |
Side by side
- Both are Action games on Steam.
- Planetary Zigma is free; Monster Mercs is paid (Price unknown).
- Both support cooperative play.
Planetary Zigma vs Monster Mercs — FAQ
- Are Planetary Zigma and Monster Mercs similar?
- They overlap on Action on Steam, so the catalogue groups them together — but "similar" depends on the specific mechanics. Use the genre + category rows above to decide whether the overlap matches what drew you to the one you've already played.
- Do both Planetary Zigma and Monster Mercs have co-op?
- Yes — both list a co-op category on Steam. Specifics differ: Planetary Zigma ships Online Co-op, Co-op; Monster Mercs ships Online Co-op, Co-op.
- Is Planetary Zigma free?
- Yes — Planetary Zigma is a free-to-play Steam title. Monster Mercs is paid (Price unknown).