The beginning was really good, I can visualize it clearly in my mind. you know how to start things I'm intrigued, but also confused... It's really really vague and when I finished reading I was like "That's it?" I just can't understand what's going on here. it got me lost. but overall, that's nice, I think we're gonna understand more since this is just the prologue, right?

Overall I'm intrigued. I think my first commentary would be that I really would like to know who this is all happening to. I don't mind that it's a little vague, but this is a LOT vague, and I think some character details might help, particularly if the person involved is of any significance whatsoever. For instance, who is the person experiencing these things? This mysterious "figure"? Maybe flesh out the character even just a little bit. Give him/her a bit of history or at least a motivation why they're doing what they're doing. You don't need to identify them, but throw in more emotion/reaction to the scenes you're writing, just to give some hints about who they are.

More detailed critique:

"his hand travelling over the worn wood of the boulder " - boulders are rock in my general experience. Maybe change this to "his hand traveled over the time-worn rock of the boulder in front of him"

"the light dancing with a light breeze" - maybe say, "the light dancing with the shadows in tandem with the breeze that flitted through." However, this little description is contradictory to what follows it. The lights dancing sounds playful and happy, but followed by fearful faces? It all depends on who is watching and what they are seeing, of course. If the person whose POV you are describing is seeing happy dancing lights that's fine, but it would be more powerful if you indicated it somehow, such as saying "the lights danced with the shadows in tandem with the breeze that flitted through, the mood of the moment a stark contrast to the fearful looks on the faces of the hooded figures that moved past, long shadows falling behind them." On the other hand, you could also make the dancing lights eerie or creepy instead, which would add to the mood more.

Depending on what is being perceived and how it's being perceived you can use that moment to give the reader some insight into the viewer - the watching figure - without actually digging into their heads. You've started out with some great details, but I think you can add a lot more without adding a lot more words. I really (personally) want to know who this person is, why they are watching, what they are really seeing and how it is affecting them. I hope this at least tells you that I like how you've started. It's a mystery, and it's good to keep it that way, but you can give a lot more detail and still keep it mysterious.

"Puddles reflected flickering torchlight, dark shadows creeping from a maze of alleyways." Puddles of what? Shadows creeping from a maze of alleyways where? Add a few words. Puddles of muddy rainwater or puddles of sewage or something. Dark shadows crept from one of many in the maze of alleyways that meandered through the darkest regions of the city.

"In a swift movement, he leapt from behind the boulder, a flash of silver in his hand." "After a series of muffled thuds, a whisper followed the arrival of the man once more." You're switching point of view here, which is a bad thing in general. If the point of view is from the silent figure at the beginning, you need to stick with that POV. Also, I think I managed to figure it out, but it isn't clear what he's doing. I assume he's jumping out from his hiding place to attack the guards who are escorting a group of prisoners. Then when he begins speaking later, I assume he's speaking to the prisoners themselves. Again, that isn't very clear. Make that more obvious.

Who are the hooded figures? You hadn't mentioned hooded figures earlier. Are these the same as the "darker" figures you mentioned at the beginning?

Overall there is a great sense of tension. You are starting to develop a good sense of mood, but it could still use some work. In particular I think it wouldn't hurt to try to really picture the scene in your head and think about all the details that make it up. It's better to write too much to start with and have to cut than to write too little and leave the reader wondering what the hell is going on. At least that's my personal experience. I think as writers we all probably have the same dilemma of dealing with a perfectly imagined scenario in our heads, but we end up leaving a lot of details in our silly brains that might be crucial to building the scene for our readers. Don't hold anything back, in other words. Not in a first draft, if you can help it. Maybe half of it is pointless, but every detail might be important at some point.