Trying to place Flock into a single genre or category is a little tricky, but the critter herding game is probably best described as a puzzle game. The goal is to lead the animals inhabiting each of the game's fifty-plus levels to your alien mothership to be abducted to serve your unnamed alien needs. Well, 'lead' is actually a little misleading, since the way that you herd animals in the game is by spooking them by approaching them with a flying saucer. When you begin to get close, the animals will do their best to head in the other direction. This is actually trickier than it sounds, and it gets trickier still as you try to herd larger groups of animals.

So far Flock may sound like an action game, an unusual action game, but an action game nonetheless. But in Flock, it's never a simple matter of getting the animals from Point A to Point B. Each level has puzzle elements to it, so you'll have to figure out the little tricks to each one in order to get the required number of animals to your goal. There are four types of animals in the game, each with its own unique ability. When sheep come in contact with water they shrink for a short period of time which lets them squeeze under fences or through small gaps. Cows can be pushed to stampede when followed closely, and stampeding cows can knock over obstacles such as trees and fences. Chickens can fly over small gaps, but they have a tendency to fly off of cliffs to their doom. Lastly, pigs are easiest to herd, but enjoy jumping into dung piles. Many levels feature a combination of animal types to be herded and you'll need to use a combination of their characteristics to overcome obstacles and get the required number of them to your mothership before your time runs out.

Each level really has two goals to it. The first is to get the required number of each type of animal to the mothership before time expires. Doing so is enough to complete the level and unlock the next. However, to get credit for 100% completion on a level you'll have to corral every single animal on the level. The difference between the two goals may seem subtle, but it actually adds enough depth to the levels to essentially turn each one into two puzzles. There are some levels that can be completed in under a minute, but that will require considerable more time to do what you need to do to recover every animal. This is further complicated by the fact that if you're not careful, you can easily spook an animal off a cliff and to its doom, which means starting the whole thing over again. This last complication can often be a frustrating one, since you'll find yourself replaying some levels several times over even though you know exactly what you need to do to complete it. That's in addition to the frustration inherit in trying to herd virtual animals, a frustration that will probably prove to be too much for the more cerebral puzzle aficionados out there. The levels are scored based on the number of animals captured and the time it takes for you to complete it and there are bonuses for bringing the animals to the mothership, so besting your old score or trying to make it onto the online leaderboards may provide you with some motivation to replay levels that you've already completed.

The game does a good job of introducing new puzzle elements along the way as you make your way through the game's 55 puzzles. There's a bit of a sense of anticipation when starting a new level in wondering what new tricks are in store for you. However, the frustrating aspects of the game can certainly wear on you at times, especially when it comes to the suicidal nature of the animals that you're herding. Perhaps they're continuously sacrificing themselves to extend your gameplay, which would be complete in a couple of evenings if it weren't for their sacrifice.

Once you make your way through the game's puzzles you have a couple of options in addition to replaying the puzzles that you've completed. The first is co-op play, which supports only local split-screen but at least features puzzles specifically designed for co-op. Puzzle games don't make for the best co-op experience and that's the case here as well, although some people may find it mildly diverting for a little while. The other option is to create new levels or to download and play user-created levels. The level designer isn't all that easy to use and once you get the hang of it you'll quickly learn that quality level design is a tricky art to master, so most people will probably want to stick to enjoying the fruits of others' labors.

In The End, This Game Hath Been Rated: 68%. There's some fun to be had in Flock … at least for the patient.