It doesn't help matters that since time began herding gameplay has never really been that much fun. It wasn't that much fun in Sheep back in 2000 (which incidentally was about aliens too), it was a concept that wasn't quite strong enough to rest the laurels of Herdy Gerdy upon, and even the goat-herding in Twilight Princess wasn't exactly stellar. The problem lies in the fact that directing a variety of out-of-control cloth-eared mammals across a cliff-strewn danger zone means that, by its very nature, you rarely feel in enough control of what's happening on-screen.
The central 'have slight control of a bunch of suicidal animals' mechanic draws such a thin line between satisfaction and screaming blue murder that it can presumably only be analysed using an electron microscope. When things go wrong and a barnful of creatures tumble from a precipice and into the drink, you feel utter frustration rather than an urge to restart the level. It gets to the point that when you restart levels you hear the solemn thud of your own mortality with every press of a button.
The joke, of course, is that technically Flock isn't particularly difficult. You'll whip through its sixty levels in little more than a particularly dreary afternoon. It's just so mediocre that when your herd goes the wrong way and renders the last three minutes of your life null and void in an official capacity you feel an urge to go outside and hurt things. This is further compounded by in-game niggles like sheep getting stuck on fallen fences, chickens leaping off whatever they can find so they can embark on a doomed cross-screen flight into the ocean while serenaded by your screams, and boulder-opened swing-gates that automatically close for no reason other than flicking two fingers at you for wilfully breaking the countryside code.
At a base level, then, I do not recommend Flock! It starts out fresh and faintly interesting, starts to move the furniture around in an increasingly desperate attempt to keep the romance alive and ends up with you developing so many emotional hang-ups and irrational outbursts of bottomless rage that all the good times are purged from your mind. It is, in short, like the most damaging relationship you've ever had.
Then again, it does have a rather good co-op mode. Sure, it isn't exactly Halo 3 or Gears of War - but even the angriest of astral shepherds would find it hard to argue that having one player flatten out crops and raise gates while the other chases the four-legged abductees around the level is a clever distillation of what makes co-op gaming the joy it nearly always is. There's also a half-decent level design kit buried in the menu system, but if you ever go beyond writing your name in cloth meadows I'd be extremely surprised.
Finally though, and most damningly, there's just no charm to the game. You go into it expecting whimsy, laughs and character (as you did in the otherwise dire Sheep, actually), but you leave having raised a half-smile at the way pits spew out lamb-chops, and a feeling of nausea whenever you hear jaunty music. I don't like it, and I've told my Dad about it and he said he didn't like the sound of it either. He told me he was going to get his shotgun, and that's where we left it.