Video Game: Newer Super Mario Bros Wii

Newer Super Mario Bros. Wii is a full unofficial sequel to New Super Mario Bros. Wii, crafted over the span of three years by a team of devoted Nintendo fans. Requires a copy of New Super Mario Bros. Wii and is playable legally on any homebrew-enabled Wii; no piracy or hardware mods needed.

A trailer (with links to Let's Plays) can be found here. Additionally, here is the developer walkthrough.

Get the game, as well as three smaller spin-offs, here.

Tropes in this game