It is "Diablo with guns". Actualy, there are a crapton of puzzle elements to make a clear distinction.
You are some freelance dude, crashlanding on a planet with precious minerals to smuggle, while there's a robot infestation ... probably from ancient times ... But that ship-AI is darn sexy.
It is a solid game, you probably did not played yet. If you find it, it can be a good bargain, and can last for a good chunk of hours.
Note though, that the final battle is .. problematic, because it involves a megaton of spawning enemies. I'm not evensure you can beat it on the highest difficulty. Until that, or on normal/easy diff it is absolutely ok, but on hard... Still, the AI is still sexy. You can feel like the Nostromo's crew in Alien fel to Mother, only this one is more like Space Hunter's android than a mother-figure.