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The Top 5 Promising Game Engines

A game engine is the foundation of any video game, being the core software in which games are developed. With most professional game engines open to the public for free, it can be hard to decide which engine to choose for your next project. This article will outline the best game engines for 2021 and try to help you in making the decision of which engine to choose for future game development.

Unreal Engine 5


Pricing: Unreleased

Developer: Epic Games

Release Year: 2021


Unreal Engine 4 has already had a huge impact on the games industry, with its high fidelity graphics, yet fast “blueprint” visual scripting work flows putting both power and convenience in the hands of indie developers. In addition, the code for the engine was open source, allowing developers to make their own modifications, something their biggest competitor Unity had never done.

screenshot from ue4 demo where an entier hall is collapsing Unreal Engine 4's Tech Demo showed off lighting and effects that were groundbreaking for its time

This year, Epic Games announced that they are bringing out a new version of their engine, Unreal Engine 5. Unreal Engine 5’s improvements over its predecessor will help developers make the most of the new hardware standards set by the upcoming PlayStation 5 and Xbox Series X. Unreal Engine has been known for pioneering graphically intensive games, from Unreal Tournament to the recently released Final Fantasy VII Remake. As the engine is developed by Epic Games, by using their engine and subsequently releasing to their Epic Games Store you gain the benefit of having a lower share of your profits taken upon release.

Why it's Relevant in the Future

Unreal Engine 5 will introduce two major features to help developers create more immersive games. The first is Lumen which will utilise Dynamic Global Illumination to help in-game AI and detailed geometry react seamlessly to changes in light without having to bake first. The second feature is Nanite which will allow developers to make use of cinematic assets without having to adjust them for the engine. This means no more worrying about high polygon counts and promises to help developers implement “art that just works”.

Further atmospheric improvements include the inclusion of better game audio, including convolution reverb to simulate caves, sound field rendering and specialized audio (something the PlayStation 5 has already been promoting it will make use of with its Tempest Engine). On the gameplay side of things, animations are meant to become smoother with new ‘fluid simulations’ and an improved Niagara effects system is meant to better simulate swarm behaviour. Lastly, the Chaos Physics System promises to not only create more realistic movement of assets in the game, but help modify IK and body position to make player animations, such as scaling a wall, more accurate with foot placement and motion warping adapting to the more accurate assets promised through use of the Nanite feature.

woman is standing in a valley, stepping in water puddles The Unreal Engine 5 Demo showed us interactive and super high fidelity environments, made possible by nanite technology



Pricing: Free (if revenue or funding is less than $100K in last 12 months)

Developer: Unity Technologies

Release Year: 2005


Unity has become a staple for indie developers due to its free price, countless online learning resources and a vast Asset Store to help small teams lacking specific skills. It was also one of the first publicly available, commercial 3D engines that focused on making game development accessible and easy for everyone, which allowed it to gain a lot of popularity in its early years.

Why it's Relevant in the Future

The reason Unity will be important in 2021 can be summed up into one phrase: Virtual Reality. With Unity being “used to create over 60% of all AR/VR content”, it will no doubt remain crucial in creating VR games in 2021. With greater accessibility of VR devices and trends in greater expenditure in the VR industry in the upcoming future, more and more people will be developing for VR. When looking at Unity’s roadmap for the future there are many interesting features in development and even more currently under investigation and being researched.

visual scripting interface for shaders in Unity

While full physical light support and visual scripting are things of the future, generic IK currently in development and major shader and lighting improvements currently in Beta, Unity is no doubt an engine that will only continue to improve. Taking a few lessons from Unreal Engine's playbook, they have focused on opening up more of the render pipeline for developers to tinker with and added visual shader scripting capabilities. Consistent aims at keeping its engine free for smaller developers and support by the developers make Unity a safe bet for 2021 no matter what type of game one wishes to develop.

Source 2


Pricing: Unreleased

Developer: Valve

Release Year: 2015

Source 2 is the successor to Valve’s Source engine, which has not seen major updates since the release of 2004’s Counter Strike: Source. For its time, the Source engine laid the graphical foundations for games that revolutionized 3D gaming, for example the Half-Life 2 games series. It was also the first engine to feature fully simulated game physics.

While Source 2 has already been used to develop games such as Dota 2, it was the release of the critically acclaimed Half-Life Alyx that showcased what the new engine is truly capable of.

player holds bottle upside down In the immersive world of Half-Life Alyx, even bottles behave the way you expect them to thanks to Source 2 graphics

Why it's Relevant in the Future

Source 2 is yet another engine that has potential to spur greater development in the direction of Virtual Reality in 2021. With support for the Vulkan Graphical API and Valve’s in-house physics engine Rubikon, its clear that this is a step up from the now fairly outdated first Source engine. While Valve has made promises to release the engine to the public for free, it remains uncertain to what extent the public will have access. While Gary Newman, the creator of Gary’s Mod, has announced that he will be working on a sandbox game based on the Source 2 engine, the general public has not gained access to the engine. If released it would be likely that many turn to the engine to develop VR games, as it would likely streamline Steam VR development. This would give Steam VR development an edge over Oculus development, who’s most prominent aid for developers currently is an asset in the Unity Store, rated at 3 out of 5 stars.

GameMaker Studio 2


Pricing: $39 (Creators License)

Release Year: 2017

Developer: Yoyo Games Ltd.


GameMaker is an enticing choice for many, due to its promises in easing the barrier of entry into game development with its own streamlined, easy-to-learn coding language and drag-and-drop functionality. GameMaker’s strength lies in 2D game development and quickly publishing game prototypes.

game maker screenshot with some code open Ease of use and accessibility lies at the core of GameMaker

Why it's Relevant in the Future

While it may not be comparable to the powerhouse that will be UE5 and doesn’t have the adaptability of Unity, GameMaker’s simplicity holds significant merit and deserves a spot on this list, for the countless new Indie developers it continues to inspire to start their own games.

With pixel art becoming an increasingly popular art style for indie devs, its seamless integration allowing devs to quickly animate sprites and work with pixels as a unit and will continue to motivate up-and-coming indie devs. Depending on what License you buy, you are free to publish to whichever platform you wish, without incurring any extra charges from the developers of GameMaker.



Pricing: Free

Release Year: 2007

Developer: Godot Community


This game engine is another very popular choice for indie game developers, since it incurs absolutely zero costs on the user and is compatible with visual scripting. It is an open source engine, meaning that all the code is publicly available and can be modified at will. Just like Game Maker Studio, Godot allows you to use pixels as a unit and animate sprites within the engine itself. This has led to the development of some beautiful games such as the recently released ‘Primal Light’, whose developers we had the honour of interviewing on our weekly podcast.

Why it's Relevant in the Future

The fact that Godot offers a non-commercial, fully open and community driven alternative makes it worth considering. While it still lacks some features prevalent in commercial game engines, consistent efforts from the Godot developers makes it worth keeping an eye on. Features like physical based rendering and virtual/augmented reality development support have already made their way into the engine, however these might not be as developed as they are on other game engines like Unity or Unreal.

hall used to show off Godot lighting Godot only recently got global illumination, a feature most other 3D engines had for a while

While programming in Godot is mainly done using its primary language called ‘GDScript’, the developers are currently working on implementing a wider range of different languages, to help game developers use whichever language they are comfortable with. The developers are currently seeking donations on their Patreon to help expand their engine’s C# functionality.

Godot’s creators have always stated that they wish to develop for the long term, ensuring that each feature they implement is done to the best of their ability, ensures compatibility and reduces the need for alteration in the future. If you want to find out more about the history and vision of Godot, consider listening to this podcast interview with Juan Linietsky, who started the Godot project.

Hope you enjoyed our list! Please leave a comment if you have your own speculations - we love hearing your thoughts!

Carlos Beaujean