This video is kind of great on the subject, 24 really shitty game covers analyzed in a comedic way.
Angry Video Game Nerd Bad Game Covers - The Complete Marathon!

I disapprove of what you say, but I will defend to the death your right to say it.

As bad as these are, and they are, they are all still WAY better than the cover of the album Paranoid.

Uhm, what has an old banjo player to do with a SHMUP?

not just any SHMUP, one of the most aggressively mediocre and forgettable SHMUPs that the Super Nintendo console has to over. it is 5 out of 10 incarnate. basically the only reason most anybody pays any attention to it at all these days is because of that cover. the people who made that cover polished a turd. it's a 100% total Mad Men gimmick to get kid you to go "WTF? what is this?" and relieve you of your hard earned allowance money after your eyes are drawn to the bizarre art on the big wall of tickets at Toys R Us. no refunds!

let me put it this way: don't buy beer you haven't tried because it has great art on the label