THE CASE FOR - "PROTOTYPE"
The most important argument in favour of this dump being a prototype is the label - it's holographic, so it would be difficult to produce and thus would make it more likely to be sent from SEGA who DO in theory have the resources to produce holograms.
Another argument is that drx has previously admitted he is not very proficient at producing level layouts - this would imply that he does not have the skill to produce hoax levels of such quality as to fit perfectly with the demo sequences.
The final argument is that a hoax produced by drx would make more sense and be generally more coherent compared to the dump we have, which is full of leftover code and crashes.
Other evidence is Tails' end-of-level sign which appears to be new art.
THE CASE AGAINST - "HOAX"
The dump we have does not seem to conform to any predicted development cycle or progression; as we commented, it seems iffy in numerous respects.
drx is a good coder, so it would not be fantastically difficult for him to edit some code from a disassembly of Sonic 1 or Sonic 2 (both of which have disassemblies made, it is worth noting) with some convincing-looking labels backed up by a phony symbol table.
The sudden $1000 deus-ex-machina is also suspicious.
Isn't the incredible similarity to Nick Arcade a little bit convenient?
Then there's the fact the level select code was found near instantly, which is iffy because the UDDDDU code isn't Sonic 1 OR Sonic 2 in origin.
The monitor roulette seems arbitrary and oddly placed; it DOES work as an explanation for the Tails box, but this seems a little too convenient and opens up unpleasant questions like "what was HPZ doing in development when the majority of the physics are still rooted in Sonic 1 mentality?".
The placement of EHZ is puzzling - why did GHZ not get overwritten? Why did they move EHZ from SLZ's place to the first level entry.
drx's lack of proficiency with level layouts could explain why HPZ is so similar to in the Wai beta - he hasn't changed it. Perhaps the poor quality of all the level layouts is because he's not very good at making them!
WHERE DO WE STAND ON THE MATTER?
We're undecided - we'd like it to be real, but we feel it's scientifically expedient to question everything even if it turns out to be false worry. Better safe than sorry.