Build, buy or borrow
Our own engine?
Kai wants to write Shard Garden's game engine from scratch. Remy asks: "Is the engine what makes Shard Garden special?"
Every part of a game is a choice to build it yourself, buy it (pay for a product or service), or borrow it (use open-source code that others share).
Two engines' terms
At the time of writing, two popular engines ask for very different things:
- Unreal EngineFree to start. A game pays Epic a 5% royalty on lifetime gross revenue above US$1 million. Sales on the Epic Games Store are royalty-free.
- GodotFree and open source under the MIT license, with no royalties. A game must include Godot's copyright notice and license, for example in its credits.
Price check
Shard Garden, built with Unreal, earns US$3 million in lifetime gross revenue, none of it on the Epic Games Store. What royalty does Epic get?
- US$100,000: 5% of the US$2 million above the first million
- US$150,000: 5% of all US$3 million
- Nothing: royalties start at US$10 million
Show the answer
US$100,000: 5% of the US$2 million above the first million
The first US$1 million is royalty-free. 5% of the remaining US$2 million is US$100,000.
Build what makes you special
The question to ask about each part: does this make players choose our game?
Shard Garden's shared garden and its co-op feel are the special part, so the studio builds those. Sign-in, payments and the engine work the same in every game, so the studio buys or borrows them: Firebase Authentication, Stripe and an engine.
Every choice has a hidden cost
- BuildYou own every bug forever, and time spent here is time not spent on the game.
- BuyPrices and terms can change, so plan how you would leave.
- BorrowFree code still needs updates, and its license has rules to follow.
Quick check
Open-source code is free, so it comes with no rules.
- True
- False
Show the answer
False
Open-source code is free to use, but its license sets rules. Godot's MIT license, for example, asks every game to include its copyright notice and license text.
Quick check
Which part of Shard Garden should Kai and Remy most likely build themselves?
- How the shared garden grows and how four friends defend it
- Taking card payments
- The sign-in system
Show the answer
How the shared garden grows and how four friends defend it
The garden is why players choose Shard Garden. Payments and sign-in are solved problems, and the services that do them are safer than a new version.
Record it
The studio writes the choice down as a decision record: "ADR 3: We will use an existing engine, because the engine is not what makes Shard Garden special." The Consequences part lists the license terms the team now has to follow.
Bolt says: Next: outsourcing, and who owns the work it makes.
Fact-checked 12 October 2026
- Unreal Engine: Licensing options unrealengine.com
- Godot Engine: License godotengine.org