A few sites mention cheat codes you can add after the executable, then use a key to activate ingame.

From GameFAQS:

https://gamefaqs.gamespot.com/pc/564955-litil-divil/cheats

litil devil codes
insert the first code on the command line and press the second code during gameplay to recieve its award. (case sensitive)
Effect Code
Level warp KmCiNpOcKeT \ [F1]
More energy MEANING \ Shift [P]
More keys Grumpy \ [K]
More money Donkey \ [T]
Next room Nicole \ Shift [P]

I tried editing the DOSBox single conf file, but when I launcht the game it produces and error and the launcher exits.

I then tried editing the divil.bat file but, while the game runs, the cheats don't sseem to work.

Anyone got an idea?

NVM, found it on Steam:

https://steamcommunity.com/sharedfiles/filedetails/?id=329586077

To keep it short, edit either the batch or single.conf file and add the argument AFTER the disk prompt.

eg: DIVIL C:\ MEANIING %1

Then you can use Shift+T to refill your energy.

The GameFAQs page contains an error Shift+P is only for the room skip cheat.

Also you can use all the cheats at once if you want.