Just a quick post to note that I played a one-shot game of this on Monday night, with the pre-generated "Trouble in Grasslake" mission from the book. We had a lot of fun, and the game seemed to work in all the places that reading it led me to expect that it would.
We had a few rough areas with certain rules, but nothing serious - they were all things that would be easily dealt with if we had a few sessions of familiarity (or just an actual book to flick through instead of a printed out pdf). We had a major conflict, which ran surprisingly easily given that it's more involved in the reading. That might be partly because a really good early roll made it fairly short, but I think that was pretty minor - the options were pretty straightforward as we dealt with each in turn. Tactically we probably should have all been thinking more seriously but that will come in time.
Most importantly, we had a great time. The mission played out well, with the major plot and main subplot both giving a lot of entertainment. We skipped one of the suggested subplots, which never quite fitted in, so no great loss there. I also mainly hit the mice with conditions as the result of failed tests, because that was what the fiction called for. The one complication that I remember came in the player turn and led to some great drama between the guard mice as an ill-advised action by one mouse became fairly public knowledge.
Overall impressions: fantastic! I am hoping to run or play some more at Kapcon tomorrow.