|New Super Luigi U|
Let's get one thing out of the way. Plot is the exact same as New Super Mario Bros U, only Mario has been removed. Mario games have never been about complex narrative... or narrative in general. Beside we don't play Mario games for story, we play for fun... or in this games case, masochism!
The game/DLC has a few differences to New Super Mario Bros U. Luigi controls radically different then he did before and now... he controls like a shopping trolley(shopping cart to the rest of you). Luigi controls similarly to how he did in the NES classic Super Mario Bros 2 so he can jump higher, stay airborne longer and has a problem stopping precisely.
Nabbit has been added to the game to take Mario's place and he seems to be designed more for newer players since he can't be killed by enemies and doesn't gain power ups from items... this means he can steal power ups so other players can't use them... making Nabbit a troll character. I personally think it was a bad choice to add Nabbit as a playable character, but that's mainly me hating getting screwed over by my cheeky nephew.
Even though it uses the same map as New Super Mario Bros U, each stage is designed differently and is shorter with a 100 second timer. This also means that the difficulty has been ramped up to NES level difficulty... like Ninja Gaiden 2 on NES difficulty! Speaking of difficulty, it seems to have an erratic and inconsistent difficulty curve that has some earlier stages being harder then some of the later ones. This difficulty could be a deterrent to newcomers, so get newbies used to New Super Mario Bros U first.
Hidden within each stage are "hidden Luigi's" and they don't do anything at all. They come in various designs from retro to modern and vary in size. Despite the playguides have hidden Luigi locations, they are only there as blatant Easter eggs.
Gamers who hate the Wiimote will be glad to know that with an update to New Super Mario Bros U, you can use the Wii U Pro Controller and the retail version of New Super Luigi U supports that out of the box. If you play the games with the kids, I say keep them on Wiimotes since they can burn energy shaking it. Using the Pro Controller is exactly the same as playing with the Gamepad in single player so it'll be an ergonomic choice to use it. 5 player co op is still the same in case you were wonder but I've honestly never heard of anyone ever playing with 5 players outside of events.
Well this was shorter then expected, but it's better then repeating my New Super Mario Bros U review. The game is punishing, but fun... until you put your hand through a coffee table.. my hands still hurts from that. It's a great game/DLC and gives us more Mario goodness but it's difficulty will make it more of a veterans only territory. I definitely think it's worth your money but go retail is my recommendation despite the price. If you do go digital, make sure if you have a white Wii U that you have an external hard drive first. Regardless, it's well worth the money but kids may get frustrated with the difficulty before you or veteran gamers do.