Sega has released a mobile version of Sonic & All-Stars Racing Transformed for iOS and Android, and has laced the game with in-app purchases.
The mobile title is currently available to purchase for £2.99 / $4.99 USD, but promotes further spend via either in-game currency or microtransactions in order to unlock all of its content.
The iOS version introduces 'Stars' and 'Rings' as digital currency, which can be either accrued in-game or purchased with real money, and used to buy new items, characters and events.
While the majority of characters and modes can eventually be unlocked entirely via in-game cash, some are available only for purchase with real money.
Players are also required to pay in-game with in-game currency each time they start a race. Alternatively, game owners can opt to pay a further $9.99 USD to unlock unlimited racing and difficulty levels.
Various character packs (ranging from $4.99 - $9.99 USD) are available, as well as a $4.99 USD 'VIP Pass', which unlocks four characters, Grand Prix mode and multiplayer.
Racing Transformed mobile also introduces Shenmue's Ryo Hazuki as a playable character, complete with Out Run and Space Harrier vehicles.
The full PC version of Sonic & All-Stars Racing Transformed is currently available for purchase on Steam for £7.49 / $9.99 USD.