When it comes to prison games on Early Access, few are going to compete with Prison Architect. However, The Escapists approaches the concept from the other side. Here, you're the prisoner, and you're trying to escape. It's out on Early Access now - I've written some (jail) sentences about it below.
Er, let's assume we're playing an innocent, wrongly convicted prisoner, eh?
This early release currently includes one map, in which you must appear to maintain your regular prison routine, while secretly plotting and pursuing your freedom. That might been digging a tunnel, creating weapons, and crafting elaborate distractions. Along the way you boost your stats through mental and physical exercise, while trying not to lose your prison job, and, eventually, escaping.
There's already a lot of game in there, playable all the way through in the single map. Still to come is a map editor to let players create challenges for each other, more prisons to escape from, and more ways to escape.
You can get at what's already there for £7.