These easily the coolest slide puzzles you'll ever try, although not much else.
Cons: Unimpressive aesthetics; A lot of trial and error initially
I never thought I'd say this, but I actually enjoyed a game about slide puzzles (you know, those things where you slide blocks until you form a picture). Normally I find these things gimmicky and annoying (admit it, most people just randomly fiddle around with these puzzles until they get the solution), but Cogs actually makes them cool.
In the case of most slide puzzles, the end goal is to form a picture. This is not the case in Cogs; puzzles have a remarkable variety of goals, requiring you to use cogs, pipes, and hammers to reach goals such as inflating a balloon, stopping steam leaks, playing musical notes, and more. Throw in quirks like 3D puzzles, two-sided puzzles (each side interacts with the other), and multi-colored steam and these are easily the coolest, most varied slide puzzles you are likely to see. The extra complexity also forces you to actually think where you put your pieces. Thus, there's less random fiddling, and less trial and error.
Well, mostly anyway. Unfortunately, since Cogs obeys the same logic as slide puzzles, new players are likely to reach many points where they fiddle around with the blocks until things magically slide into place (pun not intended). There is in fact a strategy behind everything, which becomes more obvious as the game proceeds, but the initial trial and error leads to a lot of early game frustrations. Until you get the hang of things, it feels like there's no real thinking involved. But hang in there, there is a method to the game's madness.
Of course, when it comes down to it, you're just solving a bunch of (incredibly varied and complex) slide puzzles. There are a lot of puzzles included, but not much else (even the aesthetics are incredibly basic and lack a distinguishable personality). For those who don't care for slide puzzles, this makes Cogs a pretty tough sell, but fans of slide puzzles and brain teasers in general should definitely check this one out.