Reading as everyone said Keith Courage was a pretty bad game, I probably felt influenced by it. I played through maybe a couple stages and thought it was a pretty average game.
But today, I've given it a fair chance and the game is not that bad. I find strangely addicting killing the never-ending swarms of enemies to collect gold and get new weapons. Cheap hits in the mecha stages still bother me, but the game is not as bad as I thought it was at first. Or maybe I have a high tolerance to bad games, what do you think?