I expect some of the puzzles will outfox kids below a certain age (and above a certain age, in my case), but none is a dud and each is touched by Blue Toad's sense of humour, at turns impish and avuncular, just as with the dialogue and cut-scenes. There are a few low notes in the latter's case - the Basil Fawlty-inspired hotel proprietor improves over the two episodes, but is still slightly cringeworthy - but in general the silly accents and mannerisms all hit home, and you find yourself imitating them as you wander off to the kitchen to fetch more crackers. Scum!
All this joviality is deceptive, too, because even with all the puzzles finished there's still the big question of whodunnit. The game is clever to remind you a few times that you will need to answer this at the end, but it never rams it down your throat, and this leads to mild embarrassment in some cases as you stare down the police line-up at the end of the episode and realise you haven't been paying complete attention.
In the first episode, you really will need to be alert to pick up on the clues and contradictions sprinkled across your encounters, and while the second episode is a bit easier, even in the group of four sensible grown-ups who made up my test sample - 75 per cent of whom had actual qualifications and respectable jobs you could admit to doing when asked at a party - two of us got it wrong.
Each episode lasts around an hour, and 12 puzzles means everyone gets an equal share of the limelight however many people are playing. Everything is surprisingly playable on your own, too, although the measured delivery of the dialogue is much better suited to groups, and while there is no online play this really is one of those games that doesn't need it: there is nothing to be gained by splitting the work between strangers, nor friends whose reactions you can't enjoy face to face, and indeed a lot would have to be forgone.
Even so, replay value is a big issue. Once you finish each episode you can go back and redo puzzles you didn't solve fast enough, but generally you easily remember the solutions so this only takes seconds, and there is no change to the puzzles on subsequent playthroughs. Presumably the lack of variety is a cost-saving measure, but it also hurts the game's long-term prospects, and with an overarching story set to link the six instalments the perp is always the same when you replay an episode.
Blue Toad's 17th December launch is no mistake though. At Ł10 for around two hours of content with questionable replay value it's quite expensive, but it accomplishes a lot in those two hours, and it's the nature of that accomplishment that should not be underestimated - especially at a time of year when everyone's delighted to see each other but also secretly worried about how to keep the group together after lunch but before the Doctor Who special.
In this sense, it may not have Jason Donovan in it, and you may not control it using a lump of plastic with a whopping buzzer on it, but Blue Toad Murder Files is still unmistakeably a Relentless Software game, because it makes the difficult job of entertaining a diverse group appear effortless. The strength of hold it exerts cannot be overstated, and it sets it apart from less inclusive games aspiring to the same end.