Game creation platform and tools provider Unity has gone from much-loved enabler to PR pariah this week thanks to it's proposed introduction of the Unity Runtime Fee, charging per install for the first time and - potentially - costing devs big and small millions in lost revenue.

So who could soon be in deep debt with Unity if it's unpopular fee structure swich goes ahead? Well, the top ten highest grossing iOS games in the US offers a detailed sample to peruse and while not every one of the Top 10 is a Unity title by any means - well done Dragon Ball Z Dokkan Battle, Candy Crush Saga, Roblox and Gardenscapes, all of which use other engines - the rest are on the hook…

And those BIG names are…

Monopoly GO - Scopely

Scopely’s big-hitter, a casual mobile adaptation of the classic board game has been a huge hit. However, since it runs on Unity and is raking in both downloads and cash, the developer may be in for a rude awakening if and when Unity’s new fees hit.

Royal Match - Dream Games

Royal Match has been a surprise winner this year, overtaking formerly untouchable Candy Crush saga in both downloads and revenue in July. Again however, this huge success means they would soon be liable for some huge fees. 

It's worth saying that despite being dethroned by Royal Match, King may have the last laugh all the way to the royal bank as it runs fee-free on their own 2D specialized engine.

Call of Duty Mobile - Activision Blizzard

Given Microsoft's planned Activision Blizzard acquisition’s on-going, unresolved limbo, and the many twists and turns it has taken, it's a safe bet that any revenue streams from Call of Duty Mobile will be fiercely protected should Unity push through. Expect legal challenges ahead if feathers are ruffled, especially considering how valuable mobile is for Microsoft. With a lifetime revenue of $3bn any threat to its future earnings could possible haze the deal further. 

Pokemon Go - Niantic

Niantic may still be experimenting and hunting for another hit, but Go still brings in the big money. Unfortunately both it's biggest cash cow and new entry on the horizon, Monster Hunter Now, both run on Unity. This means that Niantic certainly has something to lose having been an entrant on our top 10 highest grossing games list already accumulating more than $5bn in lifetime revenue.

Whiteout Survival - Century Games

One of the less well-known games on this list, Whiteout Survival by Century Games is just a further reminder of the ubiquity of the Unity engine. It's also a reminder that the benefit of the engine allows even smaller studios to craft big, potentially cross-platform hits.

Coin Master - Moon Active

The last of the iOS earners top ten - and a potential big candidate for Unity fees - Coin Master saw a big boost in both users, revenue and marketing spend over the pandemic period, with famous faces joining their advertising campaign. The moves paid off with the title passing $2bn in lifetime revenue. 

With Unity breaking their gaze and promising a change to their plans it's not yet clear just how these current giants will be affected. Either way there'll be some big names worrying about parting with big money come January 1 2024.