They rate a 95. Unfortunately, there's more to a good game than good looks. Power-ups and health items are colorfully displayed along your routes. At first, and for a while, these enemies are entertaining, and even a bit humorous. They're not especially intelligent, but their sheer number and unrelentingness makes them continuously formidable.
Secret areas are plentiful.
Unfortunately, I found the gameplay ultimately redundant, simplistic, not particularly satisfying, and rate it at 75. With the exception of rather annoying e-mail notes continuously popping up to tell you of virtually everything you pick up, confront, or need to know to proceed, the Interface is clean and efficient. I used arrow keys and the mouse in a classic FPS fashion. As with arcade games, a record is kept of number of kills, presumably with the thought you may wish to replay to better your score. This freedom of movement and action is essential given the overwhelmingness of the evil hordes you confront.