I thought it would be some type of slow paced fps akin to Ju-on, but you d be able to defend yourself also. 
Some enemies would spawn automatically while others require a trigger (maybe being revealed by the light or some door opening). 

Is this a point-and-click game, or an FPS or a different style of game? Does it take place in real-time, with the player having to worry about enemies on the prowl, or does the player have to trigger event flags before enemies strike?