Well, you've certainly got room for improvement. The plotline is a good setup, but your grammar and word choice is a little off-putting. Your descriptions can be a little drawn out, making the reader want to skip ahead, you should work on showing rather than telling.

"Zelsina Isle marvels in the beauty of the Mariss Ocean," This sentence doesn't make much sense, perhaps try something like "In the Mariss Ocean lies the marvelous Zelsina Isle."

"He stepped on the portion of the wet floor, slipped, and fell on his chest, sliding forward." The large number of commas here make the sentence flow a bit awkward, perhaps instead something like "He stepped on a portion of wet floor and slipped, causing him to fall on his chest and slide forward."

( "Whoa! Look out ahead! I can't stop!" he cried.) Here we already know by the dialogue that the character is speaking in a loud manner, so it would be best to either lose the ! marks or the "cried" bit. Whichever is easier to keep sentence structure for you.

"laughing a little bit. Damien laughed a little" You sound a bit repetitive here, perhaps expand your word choice? Good substitutes are bit, some, tad, or a few other synonyms.

"he shook his head in approvement." Here, approvement should be approval, mostly because of grammar and also because approvement is not an actual word.

All in all it's not bad for a start, you just need to watch your sentence structure and grammar. Try reading it aloud, often you'll catch errors that way.

Hmm, I see. Yeah, I kind of had a problem later on with the area descriptions, so I did away with them shortly after this. I do see what you mean about my descriptions, but I wasn't quite sure anyone else would be able to visualize what I was trying to capture without a bit extra. Overall, I greatly admire the time you spent in helping me see these errors. Thank you.

I also forgot, you should make it a little more clear what the characters look like. So far all I know is hair color.

Hi. Saw your post on the forums. I'll just comment on things as I go.
First thing... the slapstick is a little off-putting near the beginning. You start it with this tourist pamphlet style introduction to the islands, and then suddenly we're watching some guy slide down a ramp due to a wet floor, getting into all sorts of shenanigans along the way. It comes out of pretty much nowhere, which doesn't do much for the effect, and then you drag it on for far too long, further decreasing the humor of it. I'd rethink that whole intro, if it were me.
Also, be careful you don't shift focus too much in your word-choice. We're watching two guys wildly careen into the ocean, and then you throw this poetry at us: "The cool embrace of the ocean waters swept over the two passengers...." You can imagine how that might break the flow a little bit. Try to keep a consistent and appropriate style going.
I'm sensing anime influence. Tell me if I'm right.
I'm a little confused as to where they're getting dry clothes to change into. I read up above that all of their belongings tumbled into the ocean after them. I suppose they had water-resistant suitcases, or something?
Every now and then you put things really strangely. Here's an example: "The meat gave off a high-pitched squeal as the juices were squeezed out and dissolved on the grill." I'm trying to picture squealing meat, and it's not coming to me. All I can think of is, like, a siren or something. The lesson here is, be careful of your word-choice: make sure it's accurate, else there are going to be questions. On that same note, 'fish' is usually just called 'fish' where I come from. Not meat. But it might be different for you, so....
"Damien asked inquisitively." This made me laugh more than it probably should have. I want you to tell me what's wrong with that phrase.
One last question: why would these two become such good friends, instantaneously, despite their having met each other under such antagonistic circumstances? Some guy rams me into the water and soaks all my belongings, I'm not liable to start palling around with him. I'd probably sock him one, if anything. So I guess I'm just asking you, why would this be a realistic reaction for these two? Something to think about.

All in all, it's not terrible. Some of your description is nice, and despite that I usually hate people starting things with background material, I actually enjoyed the first couple paragraphs of this thing. The setting sounds pleasant and fairly well thought-out, which is always appreciated, and I like the names you've chosen. They seem fitting; kind of like a mixture between island cultures and Spanish or Portuguese type names.
So far, though, I'm not terribly fond of your two main characters. There's not a whole lot that makes them stand out in any memorable way. One guy seems kind of goofy, the other quasi-intellectual, but aside from that I couldn't tell you anything about them from having read this. You've got the setting down: now I think it's time you spent a bit more effort on the characters themselves. That's what really makes a story.
Keep it up, anyhow. I noticed a number of grammatical errors, but nothing extraordinary, so I didn't think it necessary to point them out. It's a good start, I'd say. Now I'm sort of curious what all you changed in the new version.

Anyway, hope that helps. Good luck.