Gotzendiener (PC Engine)

This is an action-RPG, made by Gainax. Or at least, they were involved in it's development in some way. It's odd that Gainax's most famous series tend to be about mecha (Gunbuster, Gurren Lagann, Evangelion, etc.), but their games usually have fantasy settings with no mecha at all (Alisia Dragoon, the Princess Maker series, etc.). This game is no exception to that rule.
The scneario is pretty cool: You play as a maiden who's been captured by an evil demon, and as usual, a brave hero came to rescue you, and though he did successfully kill the demon, he was mortally wounded during the fight and quickly followed the monster into death. So you take the hero's sword and set off to find your own way out of the castle.
You go around the isometric stages, solving puzzles and occasionally fighting monsters (I guess the hero must have killed most of them on his way up?). You don't have to worry about understanding Japanese for this game, as other than a couple of animated cutscenes, there's no text or dialogue, and there's nothing in the cutscenes that you need to know to progress. There were a couple of points where I got stuck in the game, though luckily there's a really excellent FAQ on GameFAQs, that not only contains a full walkthrough for the game, it also translates the plot and provides details of the tie-in merchandise that was released for it!
The game looks good, with nice animation and sprites that are detailed despite also being tiny and low-res. The music is good too, having a slightly arabian flavour to it (some people online have compared the game as a whole to Prince of Persia, and there is definitely a similar feel to it in looks, sound and atmosphere, I'm not really familiar enough with PoP to say whether the similarities extend to the game itself. (I'm mostly unfamiliar with it because I tend to die as soon as the first enemy appears.))
The only real problem with the game is that it is incredibly short and, other than the parts where I got stuck also very very easy. I completed it in less than two hours, and as I've mentioned plenty of times before, I'm terrible at games. It's definitely worth playing if you can find it cheap/free, but copies online seem to go for about £30, which does seem a bit much.