No one else has provided feedback yet; I will.
So, this is difficult to read, just on a technical level. It looks like you're at least aware of the rules regarding capitalization and punctuation—especially in regards to dialogue—but you're applying them so inconsistently it makes it harder for me to read. While yes, typographic conventions are totally arbitrary, they also help guide a reader to make it more clear to them what's going on; like most rules in writing, you shouldn't ignore them unless you really know what you're doing. A good guide for standard publication-register English typography can be found at
Practical Typography. Consistency is key.
The use of tense is all over the place. You should pick a tense (generally past or present) and stick with it. There are pro's and con's to each; I would probably recommend past, because that's the more traditional tense used in fantasy/science-fiction (although present tense is all the rage right now). Consistency, again, is key. It's much more difficult to follow action if I can't figure out how things are temporally related to each other.
I'm also confused on who the narrator is. The narrator uses words like "strange", indicating a subjective position, and the descriptions of various things are as though written by someone on Earth describing some other world, rather than something organic in that world. Finding the position of this voice and making that consistent in terms of description, characterization, and information-revealing will improve it. My recommendation is to find a narration that doesn't have any particular commentary on what's going on beyond what one of the characters perceives it to be (I believe this is known as "third-person omniscient" or "third-person limited"; I've always struggled to completely understand the difference between the two).
my writing style tends to be vague and very dialogue heavy
To me, this is an immediate red flag. I don't like reading things where it's difficult for me to figure out what's going on. I recognize there's a lot of leeway for style, but the reader not being able to follow what's going on is going to almost always be problematic.
Though, on that note, when something is "dialogue-heavy" without much description of action, it's known as "Talking Heads Syndrome", and pulls the reader out of the story. (To be fair, this is a problem I also struggle with in my own writing)
You say to expect a lot of said's, but in practice, you don't actually use very many of them; you're instead using a lot of synonyms in order to avoid it. There is a style element here, but the general recommendation these days is to just use "said" except in rare circumstances; readers are conditioned to jump over "said" without thinking much about it, whereas the synonyms tend to call more attention to themselves. Over-use of them tends to strike me as either amateurish writing, or of low-quality pulp fiction written to appeal to younger children.
Contrawise, you don't need to use "said" all the time; you can have sets of dialogue where you don't tag anything (you start to do this in a couple of places). Consider something like:
"I'm not sure that works," Susan said, gliding the knife through the first tomato. "After all, haven't they found life on Mars?"
"Not quite." I fidgeted on the stool. I never did like chairs without backs.
"But what about that rover? Uh...Curiosity? Opportunity?"
"Enterprise."
"Like the starship?"
"Like the starship." I shrugged. "Conspiracy theories abound."
With a smooth motion, Susan slid the cubes of tomato onto the waiting casserole, and started with the next one. "Well, I think that's just ridiculous."
"It is," I said with a nod. "But what can you do?"
"I'll activate the transmogrifier after dinner." The next thunk of the knife sounded louder than the rest.
The thing is, the reader should never be confused about who's speaking, and the context of where they are and what they're doing should be apparent. (Notice that despite the fact that I never actually said where they were, a lot of readers are going to assume the narrator and Susan are in a kitchen of some sort, because I'm grounding it with the image of Susan dicing tomatoes, and the narrator fidgeting on a stool). Though forgive the terrible quality of dialogue; that's completely off the top of my head (I don't currently have access to my own pool of writing).
Now, I'm not a published author or anything, so feel free to take all of this critique with a grain of salt; though I think you'll find similar pieces of advice from other portions of the Internet that cater to writers. And on the whole, they're not major things that completely revamp your writing or anything; but a few small changes here and there will, in my opinion, really improve the quality of what you're producing without interfering with the creative aspect of writing. You have good ideas, you just need to refine how they get presented.