Ah, the Virtual Boy's first and only First Person Shooter.
After a short movie that introduces you to the mansion the game takes place in (including the sounds of lightning), you will be tossed in. I must say the scrolling-rate is terrifyingly slow in the intro, but is less noticeable in game.
The goal is to find the exit out of the maze, but the time given for this is not that long, you really have to make a run for it. You can collect items, as well, including black orbs, white orbs, hearts (y'know, for energy), bullets (which you really need, since the bullets start with will only last you about two monsters), and a key which really is the first thing you must find ... besides finding the exit.
The monsters are cardboard cut-outs (just like the rest of the game), and their arms and legs tend to fall off their body once you kill them. There are different types of monsters small and big, shooting them is harder than you think when they move around in front of you preparing to hit you with their claws, this is because of the hard to control gun sight, and worse because it re-centers itself every time you shoot, meaning you have to start aiming again if the monster didn't die with one shot! Also after finishing each level, you will get to see where you are in the game by means of an overview map with routes, these routes lead to four different endings!
This game is, coupled with Waterworld, the only game based on a movie. Based on a low budget Japanese horror film that has gained some cult status..
I find the exploring the levels interesting, and here's why: because of the shortage of bullets you'll have to find your way around the monsters who are chasing you throughout the maze, it really feels like you're being chased because you can hear them approaching you, I don't know how but you can hear it if a monster is nearing you either from behind or in front of you, together with the horror-like music (in a way kinda like wario land) this really tenses things up. Plus there's a time limit which forces you to act quickly.
What is really helpful is the map when you press select on the control, this is what makes the game manageable. It shows the items, key, and exit in the maze ... extremely handy.
In short: it's clear that Insmouse No Yakata (aka Insmouth Mansion) was old even in it's tim, but if you like retro games, this game will give you a real retro feeling, just like when you play Doom now. Only Virtual Boy owners don't have to insert a bloodcode, because we get to see all the gore right from the start (ok that was a lame joke, but I just couldn't resist).
My opinion: I've heared people say it's dull and boring, I say I enjoyed it a bit because of the back ground music, "sound effects", and upbuilding tension (which granted sometimes leads to frustration). I suggest to leave this game to the collectors.