Yeah.
It stopped being fun once I realised that nothing aside from your own memory and lack of observation puts you in danger. So, not sure if you quite managed 'unfun' game entirely, but that's what puts it more in frustrating because there's something CLOSE to something I wanted but it was just a repetitive experience.
It might even have been fun if when you died a new map was generated or something, in a rougelike way.