A rumor ran through the city like static: the Tower was sealed, its doors welded, its elevators dead. The city planners said it was unsafe. Urban explorers said it was forbidden. Hackers joked it was “unblocked 77,” a mythical port number that, if you could find it, would unlock a backdoor to the Tower’s interior. For years the Tower hummed like a sleeping thing, and everyone accepted the hum as background noise.

Ready to climb? Here is exactly how to start playing in under 30 seconds.

You can slide down walls and jump off them repeatedly. Learning the rhythm of "zig-zagging" up narrow shafts is essential.

: You must navigate one giant, multi-screen level filled with lava, lasers, and turrets to reach the top and reclaim your friend.