Demo
Also said as Free trial, Slice, Steam Next Fest demo
A free piece of your game for people to try. On Steam, Next Fest is an event where many games release demos at once for visitors to browse.
A good demo sells what a trailer can only claim. A bad one gives people a reason to skip you, so it needs to be polished and to contain your best idea early. Keep it short and end it at a high point, with the wishlist button right there.
Say it
“End the demo right after the first boss, on the reveal of the second weapon. Put the wishlist button on the end screen. Twenty minutes, nothing longer.”
Where you’ve seen it
Steam Next Fest runs several times a year and many indie launches build their whole wishlist campaign around it.
Not to be confused with vertical slice
A vertical slice is an internal proof that the game works. A demo is for the public, and it needs far more polish on far less content.