A pet project of the Frostbite team has resulted in Battlefield 4 running on iOS.

It has been quite a challenge. To handle dynamic features such as destruction or moving light sources, most things in the Frostbite engine happen in realtime. This puts extra demand on performance to be able to deliver large, highly detailed worlds with superb visual quality. We were making great progress feature-wise, but hardware and software limitations forced us to either scale down the number of objects and their complexity to retain visual fidelity, or accept lower visual fidelity to cope with a larger number of objects.

This all changed when Apple introduced Metal, their new low-level graphics API, which allowed us to make full use of the hardware. Together with the latest range of hardware, Metal has created possibilities previously out of reach and for the first time we can include both high visual fidelity and a large number of objects.

To those worried that this is taking away from the development of the game proper, stop freaking out. This was just an internal challenge for the team and isn't even the full game.

(via Frostbite)