Adventure Construction Set (ACS) is not a game but a game-maker tool created by Stuart Smith originally for the Commodore 64. Initially released in 1984, it was later ported to Apple II (1985), Amiga (1986), and MS-DOS (1987).
Despite the title, ACS does not produce graphic adventures; instead, you can build top-down, tile-based RPGs, like Ultima IV. It supports turn-based battles, melee and ranged attacks, spells, shops, and much more.
ACS was the best-selling Electronic Arts title in 1985 and influenced Bethesda when they created The Elder Scrolls Construction Kit. The construction set includes two games/tutorials: Rivers of Light and Galactic Agent (the latter only in the Amiga version of ACS).
It's just a pity that the developers used the Amiga system font in all uppercase. This gives the tool a "cheap" look and feel, but on the other hand, this was the standard in 1986.
Adventure Construction Set this is a nice little gem that you should try. Get ready to share your creations with your friends.
Download for PC 
Download for Mac