Just download the NSP file, install with Tinfoil or other similar software and you're good to go.
Tested on FW 10.0.2 with SXOS. Works on ATMOS users as well.
Convertion to XCI was not tested.
Changelog:
v1.9 rev.2:
- Now in 60 FPS (switch 30/60 modes)
- New optimization system
- New main camera
- New menu: Gameplay
- New Badnik Roller in Spring Yard Zone
- New chain sound effects in Marble Zone
- New physics of Ray the Flying Squirrel
- Spring Yard Act 2 level design changes
- Mask bug fixed on big buttons at Zones
- Polishing the physics of zones
- Correction in the Shaders of Labyrinth Zone
- Option to enable/disable Air Jump
- Change(B) button is used as a back function in the options
- Removed cameras option
- Super animation fix
- Fixed bugs on platforms
- General review of the game by Beta Testers
- Updated credits
v1.9:
• Competition connections fixed
• Marble Zone glass platform bug fixed
• Scrap Brain light arrows bug fixed
• Credits bug fixed on classic mode
• New Encore Ending with Sonic Band
• Scrap Brain and more zones, optimized for performance
• New options menu by Sonic 3
• Smooth/ fixed camera on screen option
• End of letters in version
v1.4.H:
• New smooth camera view (from Sonic 3 SMS. Timelines)
• Switch player camera (Smooth / Fixed)
• New option menu "Players"
v1.3.H:
• New Mighty Jump Dash animation;
• Jungle Zone 1 improvements and wood floating in the water.
v1.2.H:
• Super Button (transform / untransform)
• Press 4x on version to unclock cheats