Frontline Protocol is an RTS with deckbuilding and auto battler elements, entirely focused on cooperative PvE. It features a tactically rich card system: you draw from three customizable decks at once, rewarding specialization, deck planning, and player experience, allowing you to control each frontline with precision. Whether solo or in online co-op with up to three players, each battle brings new challenges. You share resources, spawners, and eco buildings. Your deck composition lets you focus on specific roles - such as economy, defense, support, or aggressive frontline control using light infantry. Communication and timing are crucial, as whatever one player builds benefits the whole team. Throughout the game, you earn booster credits that can be spent on new card packs. These packs include new cards, temporary bonuses, and resources to further develop your decks. Some cards can also be upgraded, permanently lowering their deployment cost—offering long-term depth over short-term optimization. With each level-up, you gain a skill point to invest in passive bonuses—such as higher starting resources, larger hand size, or better resource rates. This adds a growing meta-progression system that deepens your playstyle alongside your deck choices. Experienced players can take on missions, randomly generated mini-campaigns with special challenges. Completing them earns mission coins used to unlock special booster packs. These contain unique deployment plans, booster items, and additional rewards that can be strategically used to optimize your loot. With over 300 cards for units, buildings, towers, and special actions, you'll find the playstyle that suits you best.