An Amazing multiplayer experience complements the single player design greatly!
Playing the game is really quite simple. First there are three modes of gameplay; the main story in which up to 4 people can take control of the characters (Mario, Luigi, and two toads), and progress through the levels (even with more than one player, the levels can be progressed through and unlock more). There is a free for all mode in which everyone is competing for score, and a coin battle mode in which you compete for score. Free-for-all and coin battle only work on stages that have already been cleared.
The game is essentially easier with one player for one doesnt have to worry about other players pushing them into obstacles nor do they have to worry about what the other players are doing or the number of powerups they take from you. There are some benefits such as being able to ground pound simultaneously to clear the enemies off the screen, or jump on each other to read greater heights. It can be fun with more people if everyone is on the same page and not just throwing each other around and pushing obstacles into them (and its a great crutch to use since it essentially equates to at minimum of 5 lives per player on screen if a level is that hard). For single players there is a super guide function which has Luigi take over and complete the level for you, if you die eight times on a stage.
Control wise, there are two styles of play, single wii-remote and wii-remote and nunchuk. Controls are easy to grasp and I wont go into detail here, but there are what I consider waggle controls (shake the Wiiremote and the character will spin to go a little bit further when making a jump, shake it to move closer if you are floating on a stage, and lastly, shake it to lift obstacles). The controls are easy to grasp and not too difficult.
Presentation wise, the graphics are excellent for the game and get the job done. Sure it isnt a game that is graphical defining on the Wii but they do look crisp and clear for a game set in the Mario Universe. Most of the good looks here is the chance to see nostalgic enemies and environments in a new 480p light. Soundwise, nothing new hear in terms of sounds for the Mario universe, Mario and Luigi appear to have the same soundbites (Toad sounds just the same as they were in Super Mario Galaxy), songs sound either remixed from their classic counterparts or are all memorable. Nintendo seems to have delivered a great experience in terms of presentation here.
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The bottom line is that NEW Super Mario Bros Wii is an excellent addition to the Mario Universe and brings back the feelings of odd with the series. The gameplay is excellent, being able to play with friends on these levels is a great experience (locally, though the lack of online co-op for this is questionable though not worthy of scrutiny) but doesnt leave people who have no one to play with lacking the ability to complete the game, and the presentation Nintendo offers us here in terms of music and graphics is worth its weight in gold. For those who havent bought a Wii game since Super Smash Bros Brawl (yes there are a few of us) as well as for those who are looking for an excellent single player and multiplayer experience on the Wii, New Super Mario Bros is a game to get.
Note: The Red case design and boxart is amazing and I hope Nintendo does more like it in the future