If potty humor isn't your thing, then chances are good that Stacking wasn't made for you. On the other hand, if jokes like "There once was a man from Nantucket ..." have you chuckling to yourself, then Stacking is right up your alley.

Set in the fictional land of Russian Matryoshka dolls, otherwise known as "nesting" dolls, Stacking chronicles the adventures of Charlie Blackmore. Charlie's a little runt of a doll whose entire family (save mom) has been kidnapped by the evil Baron and forced into hard labor. With no one else to turn to, Charlie has to use his wits and his creative stacking ability to outwit the bad guys, save his family and put an end to the evil industrialists once and for all.

Every doll in the game has a special ability; however, only Charlie and the Baron have the ability to stack with other dolls. In order to stack, you must get behind a doll that is exactly one size larger than you and jump inside. Once inside, you have full control over that doll as well as its special ability.

Early on, you only have access to a limited number of doll sizes, but as the game progresses, more and more doll types will be opened up. The bigger dolls are often physically stronger, but that doesn't mean they are always better. Often it is the smaller dolls that are the only ones who can navigate through certain areas. Choosing the correct doll is key to solving many of the game's puzzles.

Speaking of puzzles, one aspect of Stacking that really stands out is the manner in which it presents its puzzles. Each of the four main areas in the game features a number of puzzles that must be solved in order to progress the story. Moving on only requires the player to solve each puzzle once, but for the completionists (and creative types) out there, Stacking offers up multiple solutions to each puzzle.

For example, in the first puzzle that you face, you must figure out how to empty out an exclusive club. Options include fouling the air, sneaking in through a vent or seducing the guard with a lady doll. Though the story progresses once the puzzle is solved, the puzzle itself immediately resets, allowing you to attempt another solution right away. You can keep at each puzzle until every possible solution is uncovered or move on and then return later. Yes, there are Achievements involved with solving everything.

In an inspired move reminiscent of the early days of gaming, where cheat books were printed with invisible ink, Stacking includes an on-demand hint system. Each puzzle allows you to view three different hints, with each hint revealing progressively more of the solution. It's nicely implemented because it allows for just the level of help you might need if stumped, while preventing any accidental viewing.

The aforementioned potty humor appears throughout the game — one of the core puzzles is solved by lighting your farts on fire — so it helps to have a slightly twisted outlook when brainstorming solutions. With that said, the humor is pretty spot-on and is guaranteed to have you cracking up when you least expect it.

Aside from the core puzzles, Stacking also has activities in the way of "hi-jinks." These are basically mini-achievements within the game that are nothing more than screwing around with the different NPC characters you can find. For example, one has you "dispensing justice" with a judge by running around and slamming your gavel. Another requires you to slap other dolls in the face with your gloves. These don't serve any core purpose in the game, but they are nifty little time wasters.

Finally, there is the doll collection. Stacking has a number of generic NPC dolls that are duplicated throughout, but each section also has special "unique" dolls, which only appear once in each level. By stacking within these unique dolls, you automatically add them to your collection. It may not be Pokémon, but most players will probably be motivated to "catch 'em all."

As a sub-goal within the doll collection, there are the matched sets. These are usually a themed collection of unique dolls. Stacking inside each one individually adds them to the collection, but managing to stack a full set together (without any generic dolls) unlocks a side story and a mini-movie.

Visually, Stacking looks good, with a design aesthetic that plays off the entire doll motif. Each world is created as if it were a diorama for the dolls. Items are used with purpose, but they aren't all based in reality. A perfect example is the cruise liner. All of the smokestacks are actually cigars, and the jungle animals on the safari are cardboard replicas. It's a bit kitsch but completely appropriate.

One design choice that stuck out as a bit odd was the silent film approach. From a creative standpoint, it makes sense, but from a playability standpoint, it seemed to make the movie sequences drag. The dialogue cards always seemed to hang out on-screen for an inordinate amount of time.

Last, but not least, are the controls. For a game where the main characters have no arms and no legs, Stacking controls surprisingly well. Movement was smooth, solid and responsive. It was always easy to tell where the dolls could and could not go — very important in a puzzle game.

Deceptively cute, strikingly subversive and creatively inspired, Stacking appeals to both the casual and hardcore audiences in a single shot. The game is short enough to play through in a single day, but all of the optional content means there is plenty to do after the credits roll. If Double Fine keeps putting out downloadable titles of this caliber, it may never have to release another disc-based game.

Score: 8.5/10