Wolf Kanno, I can see your point. What I find different about Zodiac Spear from the examples you mentioned is the fact that you can screw up your chances to get it very early in the game. I mean - I know there's still the chest in Henne Mines to boot, but that's really time-consuming way to get it.

Oddly, if there wasn't a way to get Zodiac Spear in Necrohol of Nabudis (and the only place to get it would be Henne Mines), I would be ok with that. Maybe I'm crazy, but I don't like punishing players for doing what they're supposed to do (= opening the treasure chests).