It looks strikingly similar to the D&D Tower of Doom and Shadow Over Mystara coin-ops, but different enough not to raise legal issues. The D&D games were quite similar to the fantasy beat'em-ups that came before them, like Knights of the Round and the Golden Axe series.
And hey, at least it's cloning a great game. I can't exactly say as much for all the Diablo II clones out there. Diablo II was a solid 'B' title, in my opinion, not an 'A'. The D&D coin-ops were 'B' titles, as well.... though they weren't soiled by outdated graphics, broken skill trees, constant patching which screwed over high-level players by horridly nerfing certain skills, and to top it all off, a crappy server (battle.net was WEAK).
*cough* Yes, Diablo II left me a little bitter...
