What is the difference between a prototype, a vertical slice and an MVP?
A prototype answers one question and throws the rest away: does this movement feel good, does this economy hold, is this loop worth building? It is deliberately ugly, usually grey-boxed, and judged only on whether the answer it produces is trustworthy. A vertical slice is the opposite trade — a small piece of the game built to final quality, art, audio, UI and all, so a publisher or an investor can see what shipping looks like. An MVP is a third thing again: the smallest version real players can play end to end, built to be extended rather than discarded. Confusing the three is the most expensive mistake in pre-production, because a slice scoped and priced as a prototype gets built to prototype quality and then shown to a publisher.
