The game currently is available for WP8 devices with 1GB of RAM .
Subway Surfers, the popular endless runner, is finally available for Windows Phone 8 users . The game is currently available only for 1 GB of RAM devices, while 512 MB RAM support is coming soon.
So Lumia 520 users will have to wait for the update, rest can head to Windows phone store to get the game. The game runs smooth as such on most of the Windows Phone device, but it still have some bugs to be taken care of. Also, Windows Phone users don’t have access to all the limited characters that iPhone/Android users have had in the past.