Flock may be fairly enjoyable to play but don't expect perfect control, variety, or wit-based challenge by any means
In Flock you control a UFO for the sole purpose of rounding up either sheep, cows, chicken, or pigs into your mothership, and the only method you have at your juncture is to cause them to flee in the direction that they are being chased by your UFO, using a regressor and depressor beam to clear pointless obstacles along the way. So as you can see the narrative is very simple, but the problem is that there is 0% plot to it -- you begin taking part in such actions from the get go without as much as a brief pretext. No matter how friendly of presentation a game may have to the player it is still mandatory for there to be a reason why you should do something as pointless as rounding animals when so many other alternatives exist that could serve as a foundation instead.
There are 60+ levels to choose from and each level is framed as a gravestone with a corresponding number at its center. You will be placed into an interface where you move the mothership around a small perimeter that reside the 60+ levels for you to select. Upon selecting a level with the R trigger it will load and be confirmed with the A button, but it's impossible for you to know what level you are selecting a second time around unless you remembered the layout in your head; and seeing that once you confirm a level you will only be aware of the capture-quota and a time limit to receive a gold, silver, or bronze medal this can only be seen as a factor of laziness on the developers' part.
Now I will follow with the pros and cons of Flock:
--Pros:
*---There are levels varying from day to night to participate in
*---The graphics are above average and appeal greatly during night stages
*---Crop circling with stone tablets slightly stands out from the monotony
*---You are able to create your own levels in an editor mode
*---The achievements are not difficult to receive
--Cons:
*---The levels never offer you much of a challenge: everything is straightforward and tedious without a need for analysis
*---There is no plot
*---There is no logical proof why the variable environments look the way they do, why only a specific number of a specific type of animal are in that environment, and so on and so forth
*---Your "depressor" and "regressor" are only there to pick up objects or flatten objects that stand in the way of your flock, they can't actually be used to directly support the flock you are trying to direct
*---The levels never really change in their variety at all, it's usually a differing landscape color in combination with obnoxious obstacles such as gophers that will physically throw your flock for no reason
*---The flocks' AI tend to be faulty: they will occasionally kill themselves because of bad control, they will be stuck in corners causing your beam to be ineffective, or they will continuously gyrate
*---There is little to no reward aside from a Blank rock after beating every level
*---Because of your inability to see the layout of a completed level before replaying it another time and the poor controls accompanying the game it is practically impossible to say that Flock can be mastered, let alone have a skill parameter
In conclusion, Flock is a very fair game at best that could have easily been made into a much more interesting genre if the developers had offered higher budget. But seeing that they deemed it a $15 release despite the deficiencies that I had mentioned it is too lenient to offer a rating above a 6 for any finalized answer.