Picture this: players start with a handful of basic strike and defend cards and a branching map of encounters. Every battle won drops new cards to draft into the deck. Every card changes how they approach the next fight. The run ends when HP hits zero or they reach the final boss. Then they start over, smarter.

Summer Engine helps you build that loop through conversation. Describe the card combat you want, the enemies, the relics, the map structure. The AI sets up the systems while you focus on what matters: designing cards that feel good to play and encounters that challenge the player to think.

The best deckbuilders are built on hard choices under uncertainty. Which card do you pick? Which path do you take? Which cards do you remove to thin your deck? Every system in this genre feeds back into making each choice feel like it matters. That is the game you are here to create.

• Solo devs who want to build a deckbuilder without spending months on the card engine plumbing.
• Designers sitting on a spreadsheet of 200 card ideas who need a way to start playtesting them.
• Anyone inspired by Slay the Spire, Inscryption, or Monster Train who wants to create their own take on the genre.
• Small teams aiming for a vertical slice they can pitch to publishers or bring to a games festival.

• Card Design Sandbox

  Get a working card combat system running fast so you can focus on designing synergies, mana curves, and power spikes.

• Roguelike Vertical Slice

  Build a 3-act demo with procedural maps, boss encounters, and enough meta-progression to hook playtesters for multiple runs.

• Steam Next Fest Demo

  Create a polished 30-minute demo loop. Enough content variety for streamers to play differently each time. Wishlist conversion starts here.