Object-oriented game engines are not wrong.
They are just old.
The inheritance tree that saved your last project could be the very thing that kills your next one.
And there is a language quietly rewriting the rules of what a game engine can even be—and most of the industry is still looking the other way.
The game development world has shifted under everyone’s feet. Slowly at first. Then all at once. The C++ veterans felt it. The Unity developers felt it. Even the indie game community felt it – that growing sense that something fundamental about how we structure game code needed to change.
Read this article to the end. Whether you write Python, C#, Java, Go, or C++ professionally, what I am about to show you will change how you think about software architecture. Permanently.
I cover five things here:
- Why classical OOP inheritance breaks down in game engines
- What Entity-Component-System (ECS) is—in plain language
- Why Rust is uniquely suited to ECS
- The honest pros AND cons of Rust for game engines
- What Rust newbies must understand before writing a single line
What Is Actually Wrong With Object-Oriented Game Engines?
Nothing – at first.
In the early days of your project, the class hierarchy makes perfect sense. You have a Character. From Character you derive a Player. From Player you derive a SwimmingPlayer. Then you add flying. Then shooting. Then you need a FlyingShootingSwimmingPlayer and you stare at your screen wondering how you got here.
Have you ever untangled a 12-level inheritance chain at 2 a.m. before a ship deadline?
Have you ever added a feature to a base class and watched it silently break five subclasses downstream?
Have you ever asked yourself, why does my beautifully designed architecture feel like spaghetti? I started with clean, textbook OOP. Where did it go wrong?
This is a structural problem.
Classical inheritance in game engines creates tight coupling by design.
A Player extends Character extends Entity chain means that when the Entity changes, everything trembles.
When you need behaviour that cuts across multiple inheritance branches—say, an NPC that can swim AND be on fire AND carry a weapon—you hit the diamond inheritance problem, or you resort to mixin hell, or you start duplicating code and quietly pretending that is fine.
And here is the deeper problem that most discussions miss entirely.
It is not just architectural. It is physical.
When you model your game world as a heap of polymorphic objects connected by pointers, your CPU cache weeps.
Every time the engine processes an entity, the processor has to chase pointers to scattered memory locations—fetching data that lives nowhere near each other. Cache misses stack up. Frame time bleeds.
You squeeze more GPU budget and wonder why performance still suffers.
The hardware is telling you something. Your data layout is wrong.
There had to be a better way.
And there is.
Enter ECS: The Architecture That Changed Everything
ECS stands for Entity-Component-System.
Do not let the acronym intimidate you. The idea is almost embarrassingly simple—and that simplicity is precisely what makes it so powerful.
An Entity is just an ID.
That is it. Not a class. Not an object with methods and properties. Just a unique integer. Entity number 4291. Entity number 18. An Entity is a label that says “this thing exists in my game world.”
A Component is just data.
A Position struct containing x and y. A Health struct containing current and maximum. A Velocity struct containing dx and dy. Components have no methods. No behaviour. No logic. They are dumb data bags—and that is exactly the point.
A System is the logic.
A MovementSystem queries every entity that has both a Position and a Velocity component, and moves it. A RenderSystem queries every entity with a Sprite and a Position. A CombatSystem queries entities with Health and DamageModifier. The logic lives in the system—completely separate from the data.
Compare this to OOP for a moment:
In OOP: “A Player IS-A Character, with methods and properties baked in.” In ECS: “A Player HAS Position, HAS Health, HAS InputController. Compose it. Don’t inherit it.”
This is not just aesthetics. This is a fundamentally different relationship between code and data.
And here is where the performance story gets genuinely exciting.
Because Components are stored contiguously by type – all Position components together in one array, all Velocity components together in another – when the MovementSystem iterates, it processes memory in a perfectly sequential pattern.
The CPU cache loves this. It loads a cache line of 64 bytes, and every single byte is useful data that the system actually needs.
No pointer-chasing. No scattered heap. No wasted cache lines.
ECS is not a new idea, by the way.
Some of the design philosophy behind Doom in 1993 leaned this direction. Dungeon Siege in 2002 used a component approach. But making ECS idiomatic, safe, ergonomic, and genuinely fast – that required a language that did not exist yet.
That language is Rust.
And its flagship game engine – Bevy (https://bevy.org/) – is the proof of concept the industry has been waiting for.
Bevy is open-source, data-driven, built entirely in Rust, and uses a custom ECS at its core. It compiles incremental builds in 0.8 to 3.0 seconds.
Developer experience is not a luxury – it is a competitive advantage.
Why Rust? Why Not C++ or C#?
Fair question. C++ has powered game engines for 30 years.
C# runs Unity, and Unity runs half the games industry.
Why does Rust even enter the picture?
Because Rust does something no other systems language does.
It makes the ECS concurrency model a compile-time guarantee.
Safe Concurrency
In a traditional game engine, multiple systems running in parallel and accidentally touching the same data is the stuff of nightmares.
Data races. Heisenbugs. Crashes that only happen on the live server under real player load. Hours of debugging. Days of hotfixes.
In Rust, a data race is a compile error. The borrow checker – Rust’s signature feature – enforces that at any given moment, data is either owned by one writer or read by many readers, but never both simultaneously.
That rule is checked before your program runs. Before you ship. Before your players ever see it.
This is not a runtime safety net. It is a compile-time guarantee. Those are very different things.
Zero-cost Abstractions
Rust’s generics, traits, and iterators are expressive, readable, beautiful to write – and compile down to machine code as fast as hand-written C.
You do not pay a performance penalty for using high-level constructs. The compiler collapses them.
No garbage collector. Ever.
Game engines live and die by frame time predictability. A GC pause in the middle of a combat sequence is a death sentence for player experience.
Rust has no GC – memory is managed deterministically through ownership rules. The frame time is consistent. Always.
wgpu for graphics (https://wgpu.rs/).
Rust’s cross-platform graphics API runs natively on Vulkan, Metal, DirectX 12, and OpenGL—and on WebAssembly in the browser.
One Rust codebase. Every platform. This is genuinely remarkable engineering.
Now—the objection that you are forming:
But Thomas, you might say – C++ has done this for decades.
Why introduce a new language with a brutal learning curve?
I hear you.
C++ can do everything Rust can do.
But here is the difference that matters: Rust enforces what C++ only recommends.
The borrow checker is the guardrail you never knew you needed – until the production crash that costs your team three weeks to debug and another week to fix.
I strongly believe the enforced safety model is worth every moment of the learning curve.
The Honest Pros of Rust for Game Engines
I believe in giving you the full picture.
So here are the real advantages—not marketing, not hype.
1. Memory Safety Without a Garbage Collector
You get C++ performance. Zero garbage collection pauses. No null pointer dereferences. No dangling references. No buffer overflows. The compiler catches them at build time – every single one. Your shipped game does not contain an entire class of bugs that have plagued C++ engines for thirty years.
2. Fearless Concurrency
Parallel systems are the default expectation in ECS architecture. Bevy automatically schedules systems to run in parallel when their data access patterns don’t conflict. In Rust, data races are compile-time errors. This means you get the performance of multi-core processing without the traditional fear of concurrent access bugs. That is genuinely new.
3. ECS as a First-Class Citizen
Bevy’s ECS is idiomatic Rust. Components are plain structs. Systems are plain functions. The architecture feels like the language – not a framework bolted on top of it. When the tool and the language share the same philosophy, development velocity goes up significantly.
4. One Codebase. Every Platform.
Via wgpu, your Rust game runs on Windows, macOS, Linux, iOS, Android, and WebAssembly. No platform-specific branches. No conditional compilation nightmares. One codebase. Ship everywhere. I think of this as the holy grail of game portability.
5. Cargo Is Extraordinary
Dependency management, build system, test runner, documentation generator, benchmark harness – all in one tool. No CMake. No Makefile archaeology. No dependency hell. If you have ever spent a day configuring a C++ build system, Cargo will feel like a revelation.
6. Performance That Rivals C++
Rust consistently matches C++ in benchmarks. Zero-cost abstractions mean the compiler does the heavy lifting. You write clean, high-level code – and the binary is as fast as anything you would write by hand in C.
The Honest Cons of Rust for Game Engines
And now for the other side of the coin – because I would be doing you a disservice if I only told you the good parts.
1. The Borrow Checker Will Fight You
Especially if you try to port object-oriented game code directly into Rust. The compiler will reject patterns that feel completely natural. You will attempt to store a mutable reference to an entity inside a component of that same entity, and the borrow checker will say no. Firmly. You will sit with that error for an hour before understanding why it is correct.
This is not a bug. It is the advantage that Rust possesses over other languages . But it is genuinely painful—and no amount of preparation fully prepares you for the experience of fighting it in person.
2. The Ecosystem Is Young
Bevy is pre-1.0. APIs change every major release. Migration guides exist, and they are good – but they require real work. If your studio needs a battle-hardened, production-proven engine today with five years of community plugins, Unity and Unreal remain the safer choice. Rust game development is the better bet for tomorrow. Be honest with yourself about which timeline you are on.
3. Compile Times Improve – But Don’t Disappear
Bevy’s fast-compile configuration achieves 0.8–3.0 seconds for incremental builds. Cold builds take longer. On complex projects, full recompiles can still test your patience. Accept this as the cost of compile-time safety guarantees. The tradeoff is real and worth it—but it is a tradeoff.
4. Scripting Integration Is Non-Trivial
Most game studios need designers and artists to write gameplay logic without touching Rust. Embedding a scripting language – Lua, Python, Rhai – in a Rust game engine is possible. It is not effortless. The tooling for non-programmer game logic is still maturing. If this is a hard requirement for your project, plan the extra development time explicitly.
5. Smaller Talent Pool
Hiring a Rust game developer is significantly harder than hiring a C# Unity developer. The community is passionate and growing fast – but the numbers are still small compared to the mainstream game dev ecosystems. Factor this into studio planning. Do not assume you can staff a Rust game project like you staff a Unity project.
Every single one of these cons is being actively solved.
By a community I strongly believe is one of the most talented, dedicated, and passionate communities in software development – except AI.
What Rust Newbies Need to Know First
I speak directly to the developer reading this from a Python, JavaScript, C#, Java, or Go background.
You are curious about Rust. You have seen the hype. You want to build games. Here is the honest path.
Start with the Rust Book before you touch Bevy.
The official Rust Book (https://doc.rust-lang.org/book/) is free, excellent, and genuinely the best foundation.
Ownership, borrowing, and lifetimes are not optional prerequisites – they are the language. Without them, Bevy will frustrate you in ways that feel arbitrary but are not.
Expect the borrow checker to reject your first fifty programs.
This is not the compiler being cruel.
This is the compiler teaching you to think about memory in ways you never have before.
Every language you have written in has been hiding memory management from you. Rust shows you the truth – and insists you engage with it. That engagement makes you a better engineer in every language you will ever touch afterward.
Do not port your OOP mental model.
A Rust game entity is not a class. There is no Player class with a takeDamage() method. Release that mental model early.
The faster you stop thinking in objects and start thinking in components and systems, the faster everything accelerates.
Bevy’s Quick Start Guide is genuinely excellent.
After Rust fundamentals, go directly to https://bevyengine.org/learn/quick-start/introduction/.
The guide builds intuition about ECS from first principles – it does not assume game development experience. Spend a weekend with it before writing anything from scratch.
Your “aha moment” is coming.
Every developer I have spoken to who pushed through the borrow checker describes the same experience.
Confusion. Frustration. A fight. And then – a click.
After that click, they never want to go back.
It clicks.
And when it clicks –
Everything changes.
The Bigger Picture: Why This Matters Beyond Games
Let me zoom out for a moment – because this is about much more than game engines.
ECS patterns are bleeding into AI agent architectures. Simulation systems. Robotics.
The “entity-component-system” mental model – separating identity, data, and behaviour – is appearing in unexpected places across the software world.
And Rust’s memory safety story has caught the attention of people far beyond the gaming community.
The US Cybersecurity and Infrastructure Security Agency (CISA) has actively encouraged organisations to move critical infrastructure code away from memory-unsafe languages like C and C++.
The White House published a report in 2024 calling for the adoption of memory-safe languages in new software projects. Rust is the language named most prominently in those discussions.
The game engine is just the proving ground.
From the bottom of my heart, I believe the data-oriented patterns being pioneered in Bevy today will influence how the entire industry builds complex, interactive, real-time systems over the next decade.
Not just games. Simulations. Digital twins. AI agents. Physics engines. Autonomous systems.
If I learn how ECS thinks about data – If I understand why cache locality determines performance – If I embrace composition over inheritance at the architectural level –
I become a better engineer in every language I ever touch.
Forever.
The Architecture Worth Building
Rust.
ECS.
Bevy.
These are not buzzwords.
They are the beginning of a new way of thinking about how interactive software is built.
The compiler will challenge you.
The borrow checker will slow you down before it speeds you up.
The ecosystem will ask you to be patient.
And in return—
You will write game code that is fast, safe, concurrent, cross-platform, and genuinely beautiful to reason about.
That is worth every difficult hour.
All the very best!
Watch this space!
References
- Bevy Game Engine — Official Site — https://bevy.org/
- Bevy GitHub Repository — https://github.com/bevyengine/bevy
- Bevy ECS — docs.rs API Reference — https://docs.rs/bevy_ecs/latest/bevy_ecs/
- wgpu — Official Site (Cross-platform Rust Graphics API) — https://wgpu.rs/
- wgpu GitHub Repository — https://github.com/gfx-rs/wgpu
- This Week in Bevy — Community Updates — https://thisweekinbevy.com/
- CPU Caches: Theory to Optimization with ECS in Rust (Medium) — https://medium.com/@jordangrilly/cpu-caches-from-theory-to-optimization-with-ecs-example-in-rust-c3d52ff99e36
- Top 7 Rust ECS Game Development Techniques (TechBuddies) — https://www.techbuddies.io/2025/12/18/top-7-rust-ecs-game-development-techniques-for-safe-high-performance-play/
- First Steps in Game Development with Rust and Bevy (JetBrains Blog) — https://blog.jetbrains.com/rust/2025/02/04/first-steps-in-game-development-with-rust-and-bevy/
- Rust vs C++ Comparison for 2026 (JetBrains Blog) — https://blog.jetbrains.com/rust/2025/12/16/rust-vs-cpp-comparison-for-2026/
The next post is a deep dive into how Rust handles OOP concepts (hint: full support but no classes—follow for more!)
