Okay, see that snaking line coming in from the right on the screenshot? That's you. And see those large round circles? Those are supposedly grapefruits, only they won't sit still - they keep moving up and down and cutting across your path. And if you touch one, you die!
That's what you have to deal with in Line Grapefruit. But that's not all - you're also on a time limit. In fact, you have a very limited amount of time to make it through the "path" (for lack of a better word). You need to snake your way through the winding trail without touching anything. The good news is that a grapefruit only kills you if it touches the end of the line - once you've made it past the grapefruit, nothing happens if it crosses the path you've made.
This is not an easy game, but it's quite unique - I can't recall seeing another game quite like it.