Basically, I enjoyed this anime because it fleshed out the background of the megaten series a bit. It is more directly based on the DDM book than the Famicom game that followed it, leading eventually to the "two men in black" splitting off from NAMCO to form Atlus. However, in general, it is fairly pathetic, even by old-fashioned standards. Taken as a compliment to the light novel, though, it works fairly well, so overall, I rated it as "good", or 7/10... however, for most people, I would recommend watching something else... leave this for diehard megatenist, or fans of the DDM light novel (which is stillnot officially in English, but there is a fan-translation).

Hope this helps.