Within the files for the Version 0.04 build are cached thumbnails depicting screenshots from a cut soccer minigame called Severed Head PK, which, per its name, would've used severed heads as balls. Despite their small size, the thumbnails are legible enough to understand what they depict: one shows a title screen, one shows a player select screen, and one shows actual gameplay. Additionally, all three images feature a much cruder art style than either the main game or NASU, the minigame ultimately added in Version 0.05. Of note is that like Severed Head PK, NASU takes place in a green field beneath a black sky and prominently features bright red assets (hills, text, and the title logo in Severed Head PK; the player character, clouds, and a strobe effect in NASU).

Given that NASU is preceded by a game selection menu with only two options present – "NASU" and "Quit Game" (the latter of which simply closes the menu) – it is unknown if Kikiyama intended to reincorporate Severed Head PK as an additional option.