I've done quite a few of these, & they all had some pressure on the screen, some worse than others. Sometimes, dark spots can be seen in the corners of the screen. Maybe the new ones fit a little better now like JOHN RISELVATO said??? I even got 1 or 2 that were manufactured backwards for some strange reason, in that the wires were sticking down into the plastic holder instead of up over it. I had to trim the middle of the plastic holder down with some wire cutters so the wires could sit in there with the backlight all the way down.
Unfortunately, the case will always bulge out a little. It can't really be helped. You could try using some digitizer tape on the sides of the plastic screen protector to hold it down. That stuff is really strong. And like others mentioned, try not screwing in certain screws near the screen too tight. Even on the motherboard too. Leaving some of them loose might help a little, though probably not completely.
As others have said, there are plenty of vocaloid songs out there with chiptune sounds in them, though they're not quite the whole song. It's at least a step in that direction though. As a small example of that, here's an old favorite of mine: