In a previous blog post we discussed the terminology used around game engines, tools and the production pipeline in game production. As a part of that work, we have researched the state of the current "game engine market" and get an overview of the most commonly used game engines.

At the time of writing the original research paper in winter of 2018, Unity claimed on their website that Unity is  [...] the world’s leading real-time creation platform. Unity is used to create half of the world’s games. This quote is on the Unity website at the time of writing this blog post, but it triggered our interest in the share of game engines used. What did Unity mean by the claim that it is used to "create half of the world's games"?

To understand which game engines are most commonly used we have taken an approach using freely accessible data from two digital game stores: Steam and Itch.io. The choice of digital game stores was based on two main factors: (1) data from the report “The State of the Industry” released in connection to Game Developers Conference 2019 stating that Steam (47%) and Itch.io (18%) are the two most commonly used digital stores for games on PC, and (2) the difference of content between the two stores. Steam represents a spectra consisting of both big- and small scale production, whereas Itch.io mainly targets indie and hobbyist developers with projects of smaller scope.

Getting information from Steam - not always an easy task...

Steam is a valuable source of data but sometimes it is difficult to get what you are looking for. There are ways though, especially if using a little manual handling. By using a script, Steam Engines developed by Github user limdingwen, we have compiled information regarding the use of game engines used in games released on Steam. 

The process was conducted in the following steps, using both the Steam Engines script and some manual editing:

The results are gathered in a table here below and in total we had 49 281 game titles including expansions and DLCs in our list. For approximately 15% of the gathered titles we found information regarding game engine used, querying Wikipedia for this. The author of the script reasoned that the script would gather engine data from notable games on Steam, with the logic that a notable game would have a Wikipedia page and also have info regarding game engine on that page.

Table 1: Game engines used in games released on Steam (data from 2018-12-20).

This approach might seem overly complicated related to the results it yields, but reliable information regarding the use of game engines is difficult to get. In hindsight, it would be wise to query more databases than just Wikipedia, and also to have a coherent list of game engines for the script to use for comparing the entries from "Identified games with other engines" - it seems unlikely that there are over 3000 game engines available. 

So, there is a  large margin of error in the data from our Steam query on many levels. For instance, when manually inspecting the results, games with a large number of expansions or downloadable contents skewed the results in favor to a specific engine (i.e. in-house engines such as Anvil and Clausewitz). We have chosen not to try to separate DLCs from the main games due to the large number of DLC packages (which is another discussion - when is a DLC or expansion a new title?).

Itch.io has data available!

To get information from Itch is easier - the information is readily available at the site. Although self reported by developers, thus not covering all games it gives a more nuanced picture of popular contemporary game engines. In the table below we can see that Unity actually had some truth in their claim about used in half of the world's games with a share of almost 50% on games published on Itch. Of course, Itch does not contain all the games in the world but it is clear that Unity is very popular among hobbyist and indie developers.

Table 2: Game engines used in games released on Itch.io (data collected 2018-12-28)

Other notable game engines used on the Itch.io platform are Construct (12 %), GameMaker (11 %) and Twine (6 %) – game engines that mostly are associated with hobbyist or indie production. It is interesting to see that Unreal is only used in approximately 3 % of the published games on Itch.io. This share is on par with special purpose game engines such as PICO-8 and RPG Maker, game engines that have a very specific target audience and use.

The overlap between our two tables of data, the top 10 game engines on Itch.io and Steam is small; only Unity and Unreal are present in both lists. None of the other engines from the Steam data set is present in the Itch.io data at all.

This blog post is based on the research paper “A Taxonomy of Game Engines and the Tools that Drive the Industry” by Marcus Toftedahl and Henrik Engström, game production researchers at the division of Game Development at the University of Skövde - a part of Sweden Game Arena. Illustrations by Rebecka Thor, University of Skövde. The paper was presented at Digital Game Research Association (DiGRA) Conference 2019 in Kyoto, Japan as a part of the Gamehub Scandinavia research project.