DOS Role Playing Games (RPG)
The Elder Scrolls II - Daggerfall (1996) is an incredibly huge open-world single-player action RPG by Bethesda Softworks. The game takes place in the middle ages on Tamriel, a fictional continent with a whopping 161,600 square kilometers and 750,000 NPCs! Daggerfall is open-ended and you can use one of the premade characters or create your own from a plethora of features. The sheer amount of things to do, dungeons to explore, quests to accomplish and people to interact with, ensures that you never get bored. Here's the PDF-manual. Download already includes a complete DOSBox installation, so no further action is necessary. You start it with the *.bat file.