Early on in Dark Seed II, Mike's mom mentions a novel that Mike is working on. It suddenly makes sense why Mike is much less of a wimpy loser in the first game: It wasn't a direct retelling of the events. It was a play-by-play written by Mike himself.
Whenever Mike uses the unusually noisy stairs in his house, he remarks "Those wooden planks creak a lot." In the dark world, it's revealed that 'those wooden planks' are a towering pile of human skulls.