Tower Defence

Core Framework

This is the approach that has evolved over the creation of several apps professionally. Areas include:

  • Trigger Action System
  • Folder Structure split based on modules of functionality, to allow scaling to multiple apps.
  • Unified input system for menus and game, using Unity’s built in EventSystems
  • Uses as many of Unity’s built in solid features as possible, for example UnityEvents.
  • Contains example of an editor script to order sprites in the scene. This approach can be powerful. (CORE_SpriteManager)
  • Set up to avoid common issues we have run into over the last several years.

Script naming convention

Prefixes are used to separate code into different areas based on it’s use case.

  • SCR_ is content code. It can be coded relatively quickly and is specific to a game.
  • CORE_ is framework code. It is shared between projects therefore needs to be more robust and resuable.
  • TRIGGER_ is for Triggers. A class that implements from ITrigger.
  • ACTION_ is for Actions. A class that implements IAction.


  • Important to have a good atmosphere : )

  • Important to have an open atmosphere. That is, an atmosphere of open conversation about how code is structured and ways of accomplishing tasks.

  • Important to have ownership and responsibility. Will make work feel meaningful. Read Extreme Ownership by Jocko Willink.


When developing apps professionally as general guidelines we do things in three phases. Prototype, Build, and Polish.

  1. Define the Target Goals for a prototype

  2. Prototype in Unity, exporting to the iPad. It is important to iterate, and hit all Target Goals simultaneously. Test with kids!

  3. Build the app based on the prototype. Test with kids!

  4. Polish the app, tweaking the graphics, interactions and minor bugs once we have a releasable app.

Best Practices

You can drag a prefab into a scene, and it just works.

Easier to test in Editor, a prefab can be tested by simply dragging it into the scene.

  • Simplifies object creation - GameObject.Instantiate() just works!

  • Easier for code to work with Edit and Continue, where I can rapidly iterate by editing code while the Editor is in Play Mode.

Content can be created and edited in the Unity Editor without code

  • Allows Designers to work in the Unity Editor directly

  • Allows Designers to be productive with less back and forth with Programmers

  • Easier to scale content creation to a large project

  • Most data is stored on prefabs as public fields

  • Example: An Designer can create a new Block from scratch by creating a prefab, and create the graphics for it without back and forth with a programmer

Leverage Unity, go with the grain

  • Public fields in the Unity Inspector should be used to hook up references between objects. This is easy to inspect and debug.

  • All object state should be viewable though the inspector, you can then click on GameObjects while in Play Mode and debug and experiment easily. There are tricks such as using [Serializable] structs which allow for inspectable sub-objects.

  • Unity’s built-in functionality is very consistent across platforms, so it will lead to less bugs when targeting new platforms.

KISS: Keep it super simple

  • Advanced language features such as Reflection have inconsistent behaviour across platforms, since the code is auto-translated, which can lead to bugs which occur only on device which are very painful.

  • Plugins are good if not too invasive, or there is a strong need that is not possible with built-in functionality (Example: DOTween, Android native functionality)

  • Keep number of lines of code as few as possible, as more code will lead to more bugs and is harder to maintain

  • Don’t over structure code. It’s good to keep state as public fields so they can be viewable from the inspector.


All of this will directly lead to less bugs, faster development, and a higher quality product. The code will be simpler, which means less bugs. This will let you focus on fun things such as making the app, instead of staying up until morning to fix an iPad specific bug. Unity will be leveraged, this will let you develop at least three times faster. This means more beach time and less working weekends time. Design will be integrated, which means you won’t have to redo the same thing three times.1

Expanding your mindset can feel like changing your religion. The hero will do this, painfully, and be reborn. Be the hero. Slay the dragon. Get the princess.

1 Relatively modest increases in productivity will lead to exponential increases in output, since the ‘rich get richer, and the poor get poorer’. Related to the Pareto Distribution. Link