It's not an overly difficult game, but there is a lot of fun to be had with it.
At the beginning of the game, we see Donkey Kong watching a TV commercial advertising the hottest toy on the market, the brand new Mini Mario toys. The ape rushes to his nearest toy store, desperate to get his hands on one of the adorable Mini Marios, only to find that they have all sold out almost instantly. Flustered, he breaks into the Mario Factory, which produces the toys, ransacks the place, and leaves with a sack full of the toys. It is up to Mario to retrieve all the Mini Marios and bring Donkey Kong to justice.
The layout of the worlds is pretty basic. You start off with six worlds, each consisting of six levels plus a Mini Mario stage and a boss fight. In the six preliminary levels you must go through two rooms to progress. In the first room, you must collect a key to unlock a door and gain access to the second room. Once you reach the second room, you must collect the Mini Mario that Donkey Kong has dropped. After six levels, you must guide the six Mini Marios that you have collected thus far and take them to a toy box. In each of the levels, you will hit switches to open up new paths, close off other paths, climb ladders or vines, collect three presents (doing so lets you try your hand at winning some extra lives), and reach your destination. The final scene in each world is a boss fight against Donkey Kong.
The game deceives you a bit and makes it seem as if there are only six worlds, which would have been a shame, as this game is not that difficult to begin with. However, after getting through the first six worlds, you unlock six additional worlds that change the gameplay just a tad. These worlds only contain the six levels with one room and the boss fight, and no Mini Mario stage per se. Instead, your objective in these levels is to collect the Mini Mario which holds the key to escape the room. The Mini Mario will follow close behind and it is up to you to figure out the best ways to navigate through each of the levels and make sure the Mini Mario makes it to the end safely.
Mario Vs. Donkey is a puzzle game at its core. You will have to find a way to navigate through each of the rooms in the time given. The first couple of worlds are actually pretty easy. You will not have a hard time solving most of the puzzles. The difficulty picks up just a bit later on, but is still no large feat. The real challenge comes in beating the high score in each level. In order to do so, you will have to complete each level as fast as possible, collect three presents in each, and, in some cases, defeat enemies for some extra points. Collecting three presents lets you play a mini-game to win some extra lives. These are really easy, sometimes rewarding you with five extra lives, and before you know it, you'll be playing with 99 full lives. It is quite possible to finish this game without ever seeing the "game over" screen. Still, its vast number of levels and interesting puzzles make for a game that's just plain fun to play.
This game has a charming visual style that's simple yet enjoyable. The character sprites are nice and are very reminiscent to the ones used in Donkey Kong Country for the SNES. It's not so much about the attention put into detail, rather than the colorful and vibrant look of each level.
The levels all have fun little tunes that keep you intent on the action. Each world has quite a few songs, so the sound doesn't get annoying. To add to this, there is quite a lot of speech. Mario will say many of his famous catch-phrases. Toad, the Mini Marios, and Donkey Kong also have a few lines.
In the end, Mario Vs. Donkey Kong is a fun puzzle game that should keep you busy for a while. It's engaging enough to draw gamers and non-gamers alike, and provides an adequate, though not grueling, challenge. You will most likely want to keep playing level after level of this addictive game. It is a little on the easy side, but it's an enjoyable game nonetheless.