This type of issue is of a main occurrence when the mod cannot find the main_init file which directly loads up the correct mod. In the steam launch settings: be sure to copy and paste exactly what is shown in the notepad for installation; next make sure the delightful decay mod is in the Amnesia folder and no where else. if this doesn't work respond back!
kdog8520
Kelson joined
My name is Kelson. I make amnesia custom stories and full conversion mods in order to give entertainment to the people who would actually play them. Need help with an Amnesia Mod? I can help. Contact me through a private message and I'll see what I can help you with. All Let's Plays are permitted so there's no need to ask. Want some voice acting in your game / mod? I can help. Contact me through Email or a Private Message and we can see how I can help.