Super Paper Mario

Super Paper Mario is a RPG-styled platformer developed by Intelligent Systems and published by Nintendo for the Wii. The gameplay is similar to the classic Super Mario games, but with the aesthetic qualities of the Paper Mario series, RPG-like elements like character dialogue and puzzles, and a blend of 2D and 3D platforming. The player starts out with only Mario, but unlocks Princess Peach, Luigi, and even Bowser through the game, and can change between them at any time.

The game was originally planned for the Nintendo GameCube in 2006, but Nintendo changed it to a Wii release due to declining GameCube sales.

Bounding Box Slowdown on NVIDIA Cards
NVIDIA cards are abnormally slow during bounding box effects even at very low internal resolutions when using D3D11. They get dramatically slower as the internal resolutions increase, even though comparable AMD graphics cards suffer no slowdown at all. This is due to Dolphin hitting a slow path on those graphics cards. It is recommended that supported NVIDIA users use OpenGL backends when playing games that require Bounding Box emulation to avoid that.

When Using Older Graphics Cards
NVIDIA GeForce 400 series and newer, AMD/ATI Radeon HD 5000 series and newer, and Broadwell integrated GPUs (Intel HD Graphics 5300+) have the full suite of OpenGL and D3D features Dolphin needs for Bounding Box - a feature this game uses for many of its effects. Older GPUs (as well as all GPUs on MacOS) lack these features, however in a workaround was added to the OpenGL backend. If you are using an older GPU on non-macOS computers, use OpenGL to avoid glitches and broken effects.

HD Texture Pack
There is a work-in-progress HD texture pack for Super Paper Mario on the Dolphin forums.