It's MP3, mislabelled as MIDI for some reason. And there are five, not six, maybe you missed a link or just had a brain glitch. I'm writing these as I listen to each song.
Game Over
This doesn't sound like 'Game Over' to me. If anything, its a 'The Stage is Set' feel.
Theme
The solo drum sections are strange. This song needs a lot more in the treble department. It's not much of a theme song, it sounds more like transition music.
Theme 2
The phasing or convulsing or whatever in the beginning section is too strong for my ears, it's sounding uncomfortable. This sounds like several clips stuck together, rather than a single theme.
Title 2
Ending/looping with a sudden cutoff leaving solo drums feels too forced. Again it feels like two seperate clips put together.
Title 3
I like the voice used for the two electric guitars. Maybe a third section with both of them playing simultaneously or with a more defined conversation would be really neat.
I find it hard to see these songs being used in an RPG, to me they sound like something for an action-arcade style game. To me, good RPG music should invoke memories or fear, or instill duties of task, or have a more 'historical' feel to them, rather than just cool sounding electronica. That isn't to say that you can't use electronica effectively in an RPG, for example, Granado Espada.