Spatial Awareness is, i imagine, the one most would fail on. I dont think theres time to do every question
Actually I managed to finish this one back when I had my stage 1 in September. I didn't have time to check all my answers thoroughly (managed to check about half of them), so might have made a few mistakes, but I was able to work them all out properly and wasn't simply guessing.
I wouldn't worry too much about it though, I think most people complete about 50-75% of it and I wouldn't be suprised if the pass mark is as low as 50% on this paper. I certainly know of people who have got through having only completed a little over half the paper.
If you do fail at this hurdle I wouldn't beat yourself up about it. Spatial awareness (particularly the kind of cube tests NATS use) requires a very specific mental aptitude, and its not one that is easily learnt (i.e. for most people you can either do it or you can't, practice will help you improve but only by so much). I think even if you are only able to get about 50% correct in the time you should be able to pat yourself on the back and safely consider yourself substantially more proficient in that aptitude than most. I know many very bright and intelligent people who are simply unable to get their heads around these and would struggle to get even 1 or 2 correct under pressure and within the time limit.