in game development, a vertical slice is a section of the game that is completely finished in gameplay, graphics, and controls that serves as a template for the rest of the game to aspire to in it's complete version.
This is a vertical slice of SWORD KINGS from page 4, where Cirocco talks to Rex about his dream - to become an adventurer and monster hunter.
Pages 1 and 4 are almost done! I'll be uploading them very soon. enjoy~