Alright, I'm curious. Have you guys ever come up with ideas, put them into being, and then realized they just don't work? Even though my game programming journey has just begun, I have.

Today, after having thought it would be an interesting idea for a while,
I decided to make a game where the other player controls your guns.
Despite being an obviously rushed "I wonder if this would even work" type prototype, the issues are pretty clear. It's like designing a racing game where the goal is to come in last. You just have to press the fire button and then line your ship up with the shots, and bingo, you scored, and the other player can do nothing about it.
Oh, but it was worse before. Before my girlfriend pointed out the horrible design in making the score work so that you have to kill your opponent while controlling his guns, there was pretty much no reason to shoot at all. Why even begin playing if playing causes you to lose?
So then I decided to switch the scoring around. Now you get points for killing yourself. And now the clever title doesn't work so well.
It still doesn't work very well for the reasons mentioned above. The game pretty much says that coming in last is winning.
We thought up some ideas, like maybe in addition to controlling the other player's shots, you control a shield mechanism on their ship or something. Or maybe I could turn it into something more Geometry Wars-esque, except the shooting is constant. However, nothing really sounded solid enough to attempt to implement.
In the end, an interesting idea that just doesn't seem to want to work.
How about you guys?