Can you escape these tricky puzzle rooms?

Physical escape rooms have become quite popular in recent years, with many of them opening up across the UK and, I assume, the rest of the world. But we should never forget how the concept started life. I remember playing several excellent browser-based escape rooms in my youth, with some of those eventually making the transition to mobile. So, if the idea of solving a series of increasingly complex puzzles to escape certain doom appeals, check out these six picks.