Roughly 73% of commercial games released on Steam are built by teams of five people or fewer, according to a 2025 analysis by Game Discover Co. That number caught me off guard the first time I saw it, because the discourse around game engines still tends to center on studio pipelines, team hierarchies, and technical directors making platform decisions. Solo developers are the actual majority of this market. And yet most engine comparison content is written like you’re onboarding a 20-person team.

I’ll be honest: I spent years as a project manager at a mid-sized AAA studio before going indie, and I assumed my AAA toolkit would translate cleanly to solo work. It did not. The engine decisions that make sense when you have a dedicated graphics programmer, a build engineer, and a QA department are genuinely different from the decisions that make sense when you’re all of those people simultaneously. So I went back and looked at the data more carefully, talked to a bunch of solo devs who’ve actually shipped, and tried to figure out what the numbers actually say.

What surprised me was how much the “best engine” question depends on what you’re optimizing for, and how rarely that gets said plainly.

Key takeaways
  • Unity holds ~45% of the mobile solo dev market; Godot has grown to ~18% of new solo projects as of 2026.
  • Godot 4.x is fully free; Unity charges $0 until you hit $200K annual revenue; Unreal takes 5% royalty after $1M gross.
  • Solo devs who ship their first game in Godot do so ~30% faster on average than those starting in Unreal, per a 2025 GDC survey.
  • For 2D games, Godot or GameMaker are almost always the better technical fit over Unity or Unreal.
  • Engine switching mid-project kills more solo games than engine limitations do. Pick and commit.

The numbers that actually matter

Let’s start with the market share reality, because it shapes everything downstream, including asset store availability, tutorial quality, and hiring help if you ever need a contractor.

Unity still dominates solo development in raw numbers. According to Unity Technologies’ own 2025 developer report, roughly 58% of all mobile games are built in Unity, and solo/micro-studio developers make up the largest segment of their user base. But Unity’s reputation has taken a real hit since the runtime fee controversy that exploded in late 2023. The fee structure was partially walked back, but the trust damage was not. A 2025 GDC State of the Game Industry survey found that 29% of indie developers had already migrated or were actively migrating away from Unity.

Godot’s growth over the same window is genuinely striking. The Godot Foundation reported that monthly active users on Godot 4.x passed 600,000 in early 2026, up from around 90,000 before the Unity controversy. That’s not a rounding error. For a completely free, open-source engine with no licensing risk, those numbers suggest a community reaching real critical mass.

Unreal Engine 5 sits in an interesting position. It’s technically extraordinary. It’s also, in my experience, genuinely overkill for most solo projects, and the 5% royalty after $1 million in gross revenue is actually the least of the friction. The real cost is cognitive load. When I briefly prototyped a solo project in UE5 in early 2025, I spent more time managing engine overhead than building game logic. That’s a me problem, partially. But it’s also a valid signal for how you should think about it.

Estimated solo dev engine usage share (2026)
Unity45%
Godot18%
GameMaker14%
Unreal Engine11%
Other / Custom12%
Source: GDC 2025 State of the Game Industry + Godot Foundation 2026 data

The real comparison: what you’re actually paying

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Pricing is where most comparison articles get lazy, so let me be precise about what each option actually costs as of August 2026.

EngineBase CostRevenue ThresholdRoyalty / FeeOpen Source?
Godot 4.xFreeNoneNoneYes (MIT)
Unity PersonalFree$200K annual revenueNone below thresholdNo
Unity Pro$2,040/year per seatNoneNoneNo
Unreal Engine 5Free$1M gross5% above thresholdSource-available
GameMaker$99.99/year (indie)NoneNoneNo
DefoldFreeNoneNone (made by King)Yes
GDevelopFree (limited) / $99/yearNoneNoneCore is open source

A few things worth saying about this table. First, the Godot number is genuinely zero, forever, including for commercial games. No gotchas. Second, Unity’s $200K threshold sounds generous until you realize that’s gross revenue, not profit, and a solo dev earning $200K gross on a game is probably netting considerably less after platform cuts and taxes. The potential for Unity to change its terms again is a real business risk that doesn’t show up in the pricing table. Third, GameMaker’s $99.99 is often underestimated as a serious commercial engine. Undertale and Hotline Miami both shipped in GameMaker. It’s not a toy.

Genre and scope matter more than people admit

Here’s where I think a lot of solo devs make a category error. They pick an engine based on what games they like to play, not what games they can realistically build alone. I did this myself.

For 2D games, particularly platformers, puzzle games, and anything with simple top-down perspective, Godot 4.x or GameMaker are almost always the right answer. Unity’s 2D tooling has improved but it’s still fundamentally a 3D engine that tolerates 2D. Godot’s scene system and GDScript were basically designed for the “one person building a medium-complexity 2D game” use case. A solo dev I know, Elena Vargas, released a metroidvania in Godot 4.1 in about 14 months of part-time work. Her estimate was that the same project in Unity would have added 3-4 months of tooling and configuration overhead. That’s not nothing.

For 3D games, the calculus changes. Unreal 5’s Nanite and Lumen make it possible for a single person to produce visuals that would have required a full lighting team five years ago. Solo scenario: a developer building a walking-sim style horror game in UE5 with photorealistic environments can produce something visually competitive with mid-budget studio work. Action taken: they accept the steeper learning curve and use Fab (Epic’s marketplace) heavily for assets. Result: first-person horror game with a 94% positive rating on Steam, ~$180K in revenue over six months, well under the $1M royalty threshold. That trade-off made sense for that project. It wouldn’t make sense for an RPG with deep systems logic.

For mobile specifically, Unity still has significant practical advantages. The iOS and Android build pipelines are mature. The mobile ad SDK integrations are easier. If your game is going to mobile and you have any hope of a live-ops model, Unity is probably still the pragmatic choice, even given the trust issues.

The thing nobody says plainly

The research here is mixed on whether engine choice actually predicts shipping success. What the data does suggest is that engine-switching mid-project is a strong predictor of failure. A 2024 analysis of 312 solo game projects on itch.io that had been publicly abandoned found that 41% had documented an engine migration at some point in their development history. That’s a staggering correlation.

My read: it’s not that engine-switching is uniquely fatal. It’s that it’s a symptom of a larger indecision problem, and solo developers are especially vulnerable to it because there’s no team pressure to commit. When I was managing a 25-person project, the sunk cost of migrating engines was obvious to everyone. Alone in your apartment at 11pm, it’s easy to convince yourself the grass is greener in Godot when your Unity project is struggling, when actually the problem is scope, not engine.

Pick based on your genre, your programming background (GDScript is easier to start with than C++, full stop), and your platform target. Then stay.

Sources

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