A recently found and posted prototype build for Final Fantasy X (speculated to be from two months before the game's final release) offers several neat debug mode treats that you won't see on the PS2 discs that Square shipped. The shot above, for example, comes from the game's battle debug room, which lets you talk to Cactuar and load different scenarios and chapters.

The following video, recorded by Knuckles500, shows an extra cutscene with an NPC's speeding Blitzball barely missing Yuna and Rikku. Notice the sped-up version of "Otherworld", already an odd song for the series:

Knuckles500 adds that there's a lot more to be found in the prototype:

"There are TONS of debugger jokes, kinda like what you find in FFVII, except more creative. ... There's a lot of weird crap. For example, one of the programmers added a bunch of party members on this really scary looking map (not sure if it's used, or even meant to be played on) -- and if you talk to them (all female btw), they do all sorts of weird animation for you (perverted animation btw). For example, when you talk to Lulu, the camera sets on her breasts as she does her 'Battle Victory pose' and doesn't stop until you press X."

[Via Unseen 64 Forums (registration required)]