Alright, this is going to be a bit more critically inclined than the feedback you've gotten thus far, so consider this your heads up.
Now first off, I have to concur that you've obviously put some thought into this, evidence of which being the most commendably scrupulous lack of grammatical errors and typos. However, there still seems to be something missing. How to say...I'm reading your writing but I'm not
feeling it. For me, the most important part of a prologue is the mood. In this case, I'd be expecting apprehension, sort of a slowly building dread, if you will. Like what I feel when I'm watching an episode of Higurashi no Naku Koro Ni (Most freakin' awesome horror anime ever <3), but no matter how I try I just can't manage to get into that mood. :\ I think the main reason here is that the pace is a bit too fast. You've got very short and concise paragraphs which, while they do relate the information, aren't right for the kind of 'HOMG I think there's something out there' sensation that I'd like to have gotten here. Really, take your time not just with the formulations but within the narrative itself, try to relate the atmosphere of the place a bit more in-depth. As it is, you're relating the events so...plainly and matter of factly. Now if you made it clear that this was narrated from say...Alakazam's point of view, that would make perfect sense, but in this case I'd have preferred less emphasis on the visual aspects (Of which, arguably, there shouldn't be very much information anyway since they can only see thanks to Charizard's tail flame) and more on the sounds and scents, the feel of that old floor they're walking on. What about temperature and humidity? These are all experienced dungeon crawlers too, so how come no-one's danger sense is tingling? Stuff like that. I'd also like a bit more visual info on the rescue team than a species list. :3
Also, two bits that stuck out:
The flame on Charizard’s tail was the only source of light for the three investigators.
This is very, VERY bare information content for being a paragraph of its own. One-sentence paragraphs can be used, yes, but typically it's to emphasize a central point or add an ironic touch to the paragraph. I'm using part of my own RP post as an example, not for self-promotion purposes but because I'm too lazy to dig up a better one:
Originally Posted by Me (Taken from the RP CARD GAMES)
"I
heard that, Smith!" she announced in her usual lethally sweet voice, "And don't you know that it's rude to keep a lady waiting? If you do not cease your inane drabbling with the peasantry and get into the cab right this instant, I shall be forced to come over and slap some sense into you again." she gave a slightly over-dramatic sigh, fanning her face with one hand, "Oh the toils I have to endure in this uncivilized backwater...and to be stuck in this cramped, stuffy car too. What indignity."
The cab driver and the four suits crammed into the backseat very prudently held their collective tongues at this statement.
See what I mean? (And please do excuse the somewhat sucky example) Using the somewhat insulting theory of funniness, the one-line paragraph is usually the zing or punchline of the previous paragraph, placed on its own for additional emphasis. In this case, however, the content of the paragraph is just a neutral piece of information without any particular significance so I'd suggest merging it with the next paragraph, especially since that paragraph is describing what the tail flame allows them to see.
Once free, Charizard stood and moved away from the slender fiend with alternating lime and black rings running down the course of its body that was now suspended helpless in midair.
Okay, now describing the beast is all well and good, but I can't say I agree with you on the timing. I mean, Charizard has just been broken free and both sides are preparing to engage in violent battle; is this really the best time to start admiring its alternating lime and black rings? o.O Personally, I would have considered the point where it wrapped around Charizard to be a more natural choice for this bit since the bit of extra time you take to describe the creature's features is - at least in my mind - lengthening the mental image of what's currently going on, which - if you changed it - would be prolonging the slow, choking process. Erm...hope that was a bit clearer than mud? xD
How to say, it's good but I wouldn't go as far as to say awesome. There are too many places where I was expecting to find description but didn't and some where I didn't want as much description but got it anyway. (The part with the rings being the prime example of this) Some of your word choices are also a bit anti-climatic (Such as using the word 'turned' for that dramatic moment when Charizard is being dragged away instead of a more dynamic expression like 'whipped/world around', things like that) Small things, but they make a big impact.
Still, this is only a prologue so I'll be checking back for the opening chapter to see how you handle it. And make no mistake, your writing is
a lot better than most of the stuff I've reviewed. Keep at it, m'kay? :3