I've played plenty of shooters as far back as Atari. The difference is Genesis II has an over reliance on trial and error. The classics have enemies that telegraph their attack/ flight patterns a little bit. They may shoot a lot of bullets that don't travel as fast, giving the player a chance to react even if it's not much of one. In your game, if you don't memorize every encounter to the last detail, you will get destroyed by something you couldn't anticipate. Regular enemies take so many shots to destroy, and the levels constantly trap you in tight corridors, leaving you no choice but to eat enemy bullets or run into the wall. I think it could have been better balanced.