BACKDOOR was my favourite, and definitely a UX nightmare. I do a lot of programming, so... a lot of programming games are trivial and borderline tedious. I was biting my nails through the whole 8 sequences of BACKDOOR, even once I thought I had it figured out. This might be terrible for some people but for me it was a really cool experience. Also, I can put processes inside processes? They feel so powerful. I could go on but I'll stop. Great game.