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Quantum Protocol
A deckbuilding card game where it's always your turn. Play as the master hackers of Quantum and take on the most dangerous malware in the world. Every action matters. Make plays, upgrade your deck, and break the enemy board!
What players say
Steam review score and the most-helpful voices, which may include critical ones. Score via SteamSpy as of 2026-05-13.
“Underrated game. Reasonably fun despite a very lengthy tutorial and "puzzle" section, which then opens to a story mode, which then opens to a roguelike. Very fast and strategic battles. Very well worth a play if you're into card games.”
— a player, Steam review · 22 hrs played“Quantum Protocol is a nice game but really difficult to complete.”
— a player, Steam review · 16 hrs played“从超时空方舟闻名而来的，打完剧情后感觉相比卡牌游戏，其实更像是陷阵之志”
— a player, Steam review · 14 hrs playedPlayer activity
Monthly average concurrent players. Live count fetched 2026-08-02 19:29 UTC · history via SteamCharts.
Latest official news
Developer announcements via the Steam news API — links go to the original posts. More across all games on the news hub.
Bug Fix
Predator enemy will now only chase cards if their health is below their base max health (instead of current max health). This matters for cases where HP is modified.
Chinese Translation Update
-- Correction of card effects and terms -- Updates to story text to read more naturally The updated story text is worth re-reading for veteran players, please give it a try :D
Bug Fixes
Fix issue with damage negation. Damage negation will now show properly in the Action Log, and cards like Taser or Vampire effects will behave more intuitively if they have their damage negated. Fix is
Small Bug Fix
Fixed an infinite combo that could softlock the game with crosscode cards.
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Screenshots
Official Steam store screenshots — click any shot to enlarge.
Facts & details
From the Steam store record, snapshot 2026-05-13.
| Genres | Strategy |
| Player tags | Anime · Deckbuilding · Card Game · Visual Novel · Class-Based · Turn-Based Tactics · Turn-Based Strategy · PvE · Rogue-lite · Sci-fi · Singleplayer · Comedy (SteamSpy community voting) |
| Features | Single-player · Steam Achievements · Steam Trading Cards · Steam Cloud · Family Sharing |
| Languages | English, Japanese, Korean, Simplified Chinese, French |
| Achievements | 11 |
| Estimated owners | 50,000 – 100,000 (SteamSpy) |
| Official site | https://www.kaiomeris.com/quantum |
Minimum system requirements (PC)
Minimum: Requires a 64-bit processor and operating system OS: Windows 10 (64 bit only) Processor: 2.4 GHz Dual Core Memory: 4 GB RAM Graphics: NVIDIA GeForce GTX 460 or AMD Radeon HD 5770 /w 1GB VRAM DirectX: Version 11 Storage: 3 GB available space