I have a little problem - I like to buy game boy games. Here is what I bought today. Not very expensive, but they don't really pay off.
Next to Kid Dracula is an interesting game called After Burst. I think it was an original game for the game boy, only in Japan. It is a bit like those 80's artillery games were you hold down the button to determine how powerful the shot will be. You would usually shoot up in the air and there was wind and stuff, then the show would fall down on the other side of the screen depending on power and the degree you aimed your cannon.
In After Burst you walk around and carry your cannon that you aim by pressing up and down. I'll borrow a picture from vizzed.com:
You shoot the egg shaped thing on each level and progress that way. Sadly, the game has terrible slow-downs. It was probably badly programmed. Other than that, it is quite interesting, I think.