Obitus is a role-playing game created by Scenario Developments and published by Psygnosis in 1991 for the Amiga, Atari ST, and MS-DOS. A conversion for the SNES version was released in 1994.
At first sight, the game looks like a classic dungeon-crawler with a first-person perspective similar to Dungeon Master, but Obitus has several distinctive points in reality. First of all, you will notice several action-triggering buttons on the main screen, such as pick, drop, eat, talk, use. They will remind you of the classic LucasArts adventures (Maniac Mansion, The Secret of Monkey Island, and more). You will have to use them properly to interact with objects and the environment. These actions can really add depth to the gameplay. Still, unfortunately, the developers didn't add a complete explanation in the manual (I suggest you find a tutorial before you start playing).
Another feature is the 3D effect: even if we are still limited to the 4 main directions, each time you turn left/right, the transition is smooth, and you can see the "angle" before the view changes to the new direction. Similarly, when you go forward/back, you don't advance immediately to the new "cell," but the transition is smooth. The result is very nice, much better than the classic pseudo-3D.
Finally, another distinctive element is side-scrolling levels. Yes, sometimes the game switches to a side-view, like Shadow of the Beast, where you have to defeat enemies using your bow. Strange choice for a dungeon crawler. The developers probably added these arcade/action levels trying to make a game that is normally quite slow, considering the need to draw the maps with pen/paper - a bit more dynamic. It works because the levels are well made and quite challenging.
In short, Obitus is a good game. It doesn't reach the quality of EOB and other masterpieces, but every dungeon-crawler lover should definitely try it.