Vertical slices
One garden, finished
The prototype proved planting works across continents, with gray boxes. Now the publisher asks Kai to show the real thing.
Unity's game development course calls this milestone a vertical slice: a part of the final game that "is fully reflective of the final product and can be played as such".
Vertical, not horizontal
Think of a game as layers: art, gameplay, sound, netcode, servers, menus.
Horizontal work finishes one layer at a time: all the art, then all the code. Nothing is playable for months. A vertical slice cuts one thin piece through every layer: one garden, one wave of pests, four players online, with final art and sound.
Quick check
Which is a vertical slice of Shard Garden?
- One garden and one wave, with final art and sound, playable by four friends online
- The art for every garden, with no gameplay yet
- All the server code, with gray boxes and no sound
Show the answer
One garden and one wave, with final art and sound, playable by four friends online
A vertical slice is small but complete: every layer, at final quality. The other two are horizontal layers that nobody can play.
What a slice proves
- The quality barThe team can make the game look and feel the way it promised.
- The real paceHow long one garden really takes, which feeds every estimate after it.
- The funWhether the fun survives with real art, sound and menus around it.
Quick check
A vertical slice should include a little of every garden in the game.
- True
- False
Show the answer
False
That would be a thin horizontal layer. A slice is one small part, like one garden, finished through every layer.
When a slice is too much
A slice costs weeks, because everything in it must reach final quality. Unity's course notes that for smaller projects, a true vertical slice can be "something of an unattainable luxury".
For a big game with a publisher, it is often the milestone the next payment depends on.
Read the numbers
1Garden 1 (slice): 6 weeks2Gardens planned: 123Team: the same 3 people
Remy says the 12 gardens will take 3 months. What does the slice say?
- Far longer: at the slice's pace, 12 gardens take about 72 weeks. Reusing work helps, but not down to 12 weeks.
- 3 months: the slice was a one-off
- Less than 6 weeks in total, since gardens share code
Show the answer
Far longer: at the slice's pace, 12 gardens take about 72 weeks. Reusing work helps, but not down to 12 weeks.
12 gardens times 6 weeks is 72 weeks. Later gardens get faster, but the slice shows 3 months is not realistic: cut gardens or move the date.
A name for "how done"
The slice is the first of several checkpoints. The rest have names every game studio uses, though not always the same way.
Bolt says: Next: milestones, from alpha to gold.
Fact-checked 12 October 2026
- Unity Learn: Production and post-release learn.unity.com