Cross-platform games: one game, every screen

The short answer

Build the game once in an engine that targets every platform you want, usually Unity for mobile plus PC, and design input, UI and saving for all of them from day one. Each extra platform then adds tuning, testing and store work rather than a second game. What gets expensive is retrofitting: a mobile game designed only for touch and portrait, or a PC game with UI that cannot shrink to a phone, needs real redesign later.

Why cross-platform is the default now

Industry analysis in 2026 keeps pointing the same way: players expect their progress and purchases to move with them between phone, PC and console, and platform-exclusive launches are becoming rare. Releasing on more platforms also spreads risk. A game that underperforms on mobile may find its audience on Steam, and a free web version can feed both.

Step 1: pick an engine that goes everywhere

Unity builds for iOS, Android, Windows, macOS, Linux, the web, consoles and XR from one project, which is why it remains the most common choice for mobile-plus-PC games. Unreal is strong for high-end PC and console and workable on mobile with more optimisation effort. Our comparisons of Unity vs Unreal and Unity vs Godot cover the trade-offs. Console releases additionally require approval from each platform holder.

Step 2: design input for every device

• Abstract actions, not buttons. Code "jump" and "aim", then map them to touch, mouse and keyboard and controller. Unity's Input System is built for this.
• Design touch controls deliberately. Virtual sticks, gestures and aim assist are game design, not a port job.
• Support controllers everywhere. Many mobile and web players use them, and Steam players expect it.

Step 3: UI that scales

The same menu must work on a 6-inch phone held at arm's length and a 27-inch monitor. Use anchored, scalable layouts, minimum touch-target sizes, safe areas for notches and foldables, and a separate layout pass for very different screen shapes. Our guide to designing for foldable screens shows how odd aspect ratios break assumptions.

Step 4: cross-progression and accounts

Carrying progress between platforms needs a player account and a backend that stores saves, inventory and purchases, with sign-in options that work on every store. Decide early which data is shared, how conflicts are resolved when two devices save at once, and how purchases appear on every platform.

Step 5: know the store payment rules

Apple and Google generally require their own in-app purchase systems for digital items bought inside mobile games, while Steam and your website have their own rules. Court rulings and new laws, such as the 2025 US ruling in Epic v. Apple that opened the door to linking out to web checkouts (a case still before the courts in 2026), keep changing what is allowed, and the rules differ by country. Design your store so payment providers can vary by platform, and check current policies before launch.

Step 6: test on a real device matrix

Step 7: stage the releases

Launching everywhere at once multiplies risk. Many studios soft-launch on one platform, fix what players find, then roll out. A free web version or a Steam demo during Steam Next Fest can build an audience before the main launch.

What each extra platform costs

If the game is designed for several platforms from the start, each additional platform mostly adds input and UI work, performance tuning, platform services (achievements, cloud saves, store integration), certification and QA. That is a fraction of the original build, not a second one. Porting a game that was never designed for it costs more; our guide to porting a mobile game to PC and Steam breaks down that work. For a quick estimate of a multi-platform build, use the cost calculator.

Related: Unity game development · PC and Steam games · Mobile games