Ommel is a mod stitcher for Noita. It functions as an extension to the existing API that allows multiple mods to change the same files without having to worry about overwriting or incompatibilities.
Since version 0.1.11 this page now distributes Ommel/Mod - a launcher for Ommel in the form of a mod. Simply put it into the mods folder and start up the game! There is no more need to mess around with launch options or commandline arguments (unless you are on Linux/Mac - check out the Ommel wiki for details).
Ommel operates on game assets directly (not using any APIs), meaning that it is vastly more powerful than doing things at runtime through Noita's API. Please note that the intention is to give extra ability to modders before the developers find a way to introduce it into the actual API, not to create a second incompatible mod loader. Ommel uses the ingame mod manager to determine which mods to load and it uses the same folder structure. Ommel is aware of non-Ommel mods and Noita is aware of Ommel mods' presence.
Open source on GitHub: NoitaOmmel organization
Learn more: Ommel Wiki
@"Kamakazi_Llama" You can do that, yes, and it's actually quite simple - you can learn more on the Ommel Wiki.