Demos and vertical slices are often perceived as the same thing. In fact, they are different tools that solve different problems.

A vertical slice is a fragment of a game assembled so that you see the finished product.

It includes the basic mechanics, interface, visual style, and pacing.

Its purpose is to test whether the game itself works.

If the entire project looks and feels the same, will it be a good game?

A vertical slice is primarily needed by authorities, publishers, and investors.

It's a way to see the project in reality, not as a projected project.

A demo, on the other hand, is created for players.

Its goal is to introduce the audience to the game and generate interest.

Therefore, a demo can:

- Be the text of the main game

- Show only a portion of the mechanics

- Intentionally focus on the strongest points

- Observe progress in convenient presentation locations

If a vertical slice is a design check, then a demo is a project showcase. Sometimes a vertical slice truly becomes a demo. But this only happens when the game fragment is already stable and understandable to the outside world.

Typical Mistake

Teams often start preparing demos too early—before the game itself has been proven to work. As a result, the developers try to show a game that hasn't yet fully developed.

Mechanics change, the pacing is unstable, and players' impressions are formed based on raw experience.

Therefore, the correct approach is:

1) First a vertical slice,

2) Then a demo.