Video Game Terms: Vertical Slice

A vertical slice is a subset of a game which demonstrates almost all of the core systems or end-to-end features working but only over covers a limited amount of the total content expected for the finished game.

Usage: "Our publisher will give us the next tranche of money to complete "Shotgun Rampage 5" if we can demo a vertical slice of the entire 1st level of the game."

Translation: "You'll get the money to complete your game when you can show that you've already pretty much completed your game."