Or this is intended to be played from start to game over in one session?
I am not asking about emulators and tweaks to save the game, I am asking about the original gameplay/design choice,
I want to play following their decisions.

I am quite sure there are no save game states. The game should not last more than 30 minutes anyways. You have to get into a completely different design mindset when you go back to the 80's dictated by limited technology, short development cycles and extremely limited storage space/compression. Couple this with how many Amiga users did not own a hard drive.

Due to Cinemaware's emulation, the game's state is saved when you exit the game. If you want to start over, there's a reset button at the title screen, otherwise you will continue playing from the moment you left off. That's a very useful feature for folks like myself who may have to suddenly interrupt a game to answer the door or a phone or something. You can't 'save crawl' in this game or create multiple save files unless you know how to find, backup, and replace the save state data files (I made a half-hearted attempt to do so and wasn't able to find where the files are located).