Good Bad Bugs: In certain emulators, a glitch involving resetting the game allows you to initialize all high scores to zero. Perfect if you keep track of your scores, because the lowest default high score of 1.2 million can take weeks of practice to attain.
Scrappy Mechanic: This game never shows your total score during gameplay; it's only shown at the end of each stage, as well as after getting a high score and ending your game, which wouldn't be as big of a problem if the lowest default high score wasn't difficult to obtain for new players. This caused a huge problem at a recent shmup tournament where many players who couldn't get on the high score table either manually calculated their scores by hand or simply didn't bother to submit scores.