You can download it here. It works basically the same way as the SADX Mod Loader and SA2 Mod Loader, except this one only does file replacements right now. To make a mod, simply create a folder containing a "mod.ini" file like so: Code: Name=Mod Name Here Author=Your Name Here Description=Describe mod here. Version=v11.q (optional) Then, create a "Data" folder in that folder, and place whichever files you want your mod to replace in their relative paths within that folder (ie Data\Sprites\Players\Sonic.bin). To use mods, extract it into the folder Sonic Mania is in, run ManiaModManager.exe, click the "Install Loader" button on the bottom, then check the mods you want to enable and hit "Save" or "Save and Play". The source code is available on Sonic Retro's GitHub.