It's still the Maniac Mansion you know and love. The graphics are an updated and glorious 256 color VGA. Animations are minimal, and noticeably so in a couple of scenes.
The soundtrack is only comprised of a few tracks, but for Midi music, it sounds really really great. Some of the tunes are still stuck in my head. A soundtrack piece is a plot device at one point.
I can't praise Maniac Mansion's gameplay enough. You sneak around the house to find and save your girlfriend. If you're caught by one of the Edisons you get sent to their dungeon, and without the right key, you're stuck. You can die too, so the sense of danger is high.