Prison-building game Prison Architect will leave Steam Early Access and launch with a brand new Escape mode and a fleshed out story mode on 6th October. That's in addition to the existing sandbox building mode.

Escape mode flips the game on its head as you attempt to break out of the prisons that either you've created with the level editor, or anyone else has created - all 12,000 community-made prisons (and counting) can be played.

Anything the prisoners can do in the game now, you will be able to do. There's a kind of role-playing game-like character progression and you can eventually become legendary in status. You can form gangs, raid armouries, dig tunnels - the whole complex prison simulation is yours to subvert.

"It started life as one of the endgame scenarios," explained game designer Chris Delay speaking to me at EGX 2015, "where if you did so badly at the game you could be convicted of corporate manslaughter if there are too many deaths in your prison. And it was a joke. I made it so that you arrived at your prison on a prison bus in handcuffs - you've been put in jail at your own prison. But you couldn't do anything; that was the end of it. It was just a joke.

"In the background we've been fleshing it out gradually until it's a whole game mode in its own right now. Anything the prisoners can do in the game, you can do, so you can steal knives from the kitchen, you can make digging implements in the workshop, you can dig escape tunnels, you can recruit other prisonsers to join up and form a little posse.

"All the stats that make some prisoners much tougher than others: they form your kind of RPG progression system in the game. So you start out as a total green newbie and as you cause trouble and your reputation grows within the prison, you get access to more and more advanced stuff. We have legendary prisoners in the game that are a total nightmare, [and] you can make your guy into a legendary prisoner.

"It's got a very different feel," he added. "It's much quicker to play. It's quite silly. It's a lot of instant fun."

The four new story chapters are "dark and funny", said Introversion's Mark Morris, and explore various prison themes over the course of around eight hours, he estimated. They also serve as a handy tutorial to the main, sandbox prison-building game.

Morris said the launch version of Prison Architect should have a noticeable "uplift" in quality reflecting its move out of a long alpha period and into its final form.

Prison Architect Escape mode is playable at EGX 2015, which is underway now in Birmingham, UK. Delay and Morris are on-stage at the time of writing, presenting Prison Architect to the EGX audience. The sesssion is live-streamed and archived below.