I took a while to get the logic puzzles, so maybe that was it. I think I would have done better at these had I been quite relaxed and had practised some other logic puzzles (look at the site I linked before). Make sure you lead the discussion of your answers, even if you don’t know what you’re doing from the start. I felt they had to prompt me quite a lot, but this was often because I was being quiet when I was thinking about an answer.
Basically, I think the reason I didn’t do too well was because I didn’t know what to expect from the interview. I asked about the interview when I got the invitation but that part of my email was ignored. Also, when asking for feedback, they didn’t give me anything constructive, just that it was an all-round technical assessment and that I didn’t meet the requirements. Bearing that in mind I can’t say exactly what they didn’t like.
You’ll be in a better position than I was because you’ll have an idea of what to expect. I didn’t know the sorts of questions I was going to be asked, which made me nervous and it must have shown. Just stay relaxed and I’m sure you’ll be able to think more clearly and you’ll come across better than I did.