Slay the Spire 2 just broke records on Steam. Here's how to make your own version — turn-based card combat, relics, branching maps, build-snowballing and all — without writing a single line of code.
Why everyone is suddenly making deckbuilders
Slay the Spire 2 hit Steam Early Access on March 5, 2026 and immediately set a genre record: 177,000+ concurrent players on day one, beating Hades 2 and Mewgenics. Indie deckbuilders — Balatro, Wildfrost, Monster Train, Inscryption, Vampire Crawlers — have racked up tens of millions in revenue over the past few years.
The recipe (cards + relics + runs + decisions) is one of the most addictive design loops ever found, and players still can't get enough. If you've ever thought "I have an idea for a deckbuilder," now is the time.
The shortcut: start from a template, not a blank file
Building a deckbuilder from scratch is hard. The card system, energy management, intent telegraphing, deck-shuffling, relic effects, run-based progression — it's a lot. The shortcut: start from a working one.
We built a Slay the Spire-style deckbuilder roguelike on Rosebud AI as a template. It's free to remix, runs in your browser, and is deliberately scoped to be a learning starting point.
👉 Template: https://rosebud.ai/play/roguelike-deckbuilder-example-1
What you get:
- Turn-based card combat with energy and enemy intent telegraphing
- Run-based progression with floors, enemies, elites, and bosses
- A card-picking loop after every fight
- Relics that modify your build
- A readable code base you can extend
How to make a Slay the Spire-style game in 5 steps
Step 1: Open the template and play it
Go to https://rosebud.ai/play/roguelike-deckbuilder-example-1 and play a full run. Pay attention to how the game feels: combat rhythm, card pickups, the deck-pruning decisions, boss design. Note what works and what you'd change.
Step 2: Fork it
Click the Rosebud watermark in the bottom-right corner and choose "Remix this game." The game opens in your Rosebud dashboard — you own this copy, and any change you make stays in your project.
Step 3: Decide what you're keeping vs. changing
Some prompts to spark direction:
- Setting: medieval dungeon, sci-fi space station, deep-sea horror, cozy bakery, Wild West
- Combat twist: add poker hand mechanics, real-time card cooldowns, dice rolls, deck-stealing
- Tone: dark and gothic, slapstick, cozy, hyper-stylized
- Genre blend: add visual novel scenes, base-building, romance, deck-trading with NPCs
A great deckbuilder usually keeps the loop (build a deck, fight, reward, decide) and changes the fiction and texture. Don't try to invent a new combat system on day one — fork first, swap the skin, see how it feels.
Step 4: Talk to Rosie
Rosie is Rosebud's AI assistant. You change the game by chatting. Plain English works. Examples:
- "Reskin every card with a sci-fi virus theme. Replace the swords with code injections and the shields with firewalls."
- "Add a new card type called 'Curse' that does 5 damage to me but draws 3 cards."
- "Make the Act 1 boss a giant clock that ages cards in my hand each turn."
- "Add a second character — a Mage with stance mechanics like the Watcher in Slay the Spire."
- "Add a tip jar so players can support me."
She writes the code. You play-test. Iterate.
Step 5: Publish and share
Hit Publish in your project. You get a shareable link anyone can play in their browser — no downloads, no installs. You can also let other people remix yours. (And if you ever want a desktop build for Steam, Rosebud's paid plans support exporting to a Windows .exe.)
Where most people get stuck (and how to avoid it)
A few traps that catch new creators:
- Trying to design everything before you ship anything. Don't. Fork the template, change one thing, play. Repeat. Small loops beat big plans.
- Describing things in vague language. "Make combat more interesting" won't work. "Add an enemy that gains 2 strength every time I play a Curse card" will. Specifics get better code.
- Forgetting to use Screenshots. Rosebud lets you screenshot the game and feed it back to Rosie when you're describing a visual change. Way more accurate than text alone.
- Not saving Checkpoints. Save often. If a change breaks the game, you want a rollback target.
- Fighting Rosie when something weird looks cool. Sometimes an AI mistake creates a mechanic you wouldn't have invented. Lean in.
The case for building now
The deckbuilder genre is exploding. Slay the Spire 2 is bringing millions of new players into the format. The best time to ship a deckbuilder of your own — even a small, niche, weird one — is right now, while attention is high.
The hard part used to be the engineering. With Rosebud plus this template, that part is largely done. Your job is the idea.
👉 Start from the template: https://rosebud.ai/play/roguelike-deckbuilder-example-1
👉 Or build from scratch at rosebud.ai
Andi Bucescu
Andi is the Head of Marketing at Rosebud, where she writes about the intersection of AI, creativity, and brand storytelling. She explores how generative AI is reshaping marketing strategies and creative workflows, with a focus on making complex technology accessible and cutting through the noise of modern campaigns. Her perspective is informed by undergraduate research on effective social media content and consumer psychology.