I’m not going to try to disguise it in the least, Altered Beast is a terrible game. It was terrible when it was new and now, over a dozen years later, it’s still terrible.
In Altered Beast you play a warrior. A dead warrior. A dead warrior who is temporarily revived by Zeus to save Athena from the forces of the underworld. So, you begin to walk to the right (you actually have no choice in this, the screen scrolls perpetually to the right, independent of your actions). Along the way you will fight throngs of evil… things, almost all of which can be dispatched by a punch or a kick. You may be an ancient Grecian warrior, but you don’t get any fancy swords, shields, or armor. You get to fight demons with naught but your bare hands and feet. Occasionally one of the thousands and thousands of identical enemies will drop some kind of power orb that allows you to power up. Powering up makes your guy stop, say, “Power UP!”, and get a sudden increase in muscle mass. Get 3 orbs and you will change into some kind of fearsome beast, suitable to take out the boss of the stage. This is convenient, since the boss will not appear until you are in crazy bloodthirsty beast form. After you beat the boss, the main bad guy, Hades, I guess, Neff (who?) steals your precious power orbs, leaving you as a weakling again. So you go to the next level and repeat the process over again, this time turning into a different animal once you grab the 3 power orbs.
That is, of course, if you can stand to play for that long. Two levels was certainly my limit.