How to modify Unity games from Steam (eg. for changing behavior, adding lots of currency/etc.)

For games with /Managed/Assembly-CSharp.dll:

1. use the updated dnSpy fork, drag and drop in the Assembly-CSharp.dll and edit the source code, then Save All, and reload game.

⚠️ NOTE: occasionally, when trying to edit and save, you'll get compile errors. To resolve this, you can try to edit the assembly directly, screenshot the lines of assembly code you want to edit into Gemini or chatGPT to edit and then paste back.