I want to echo Ken's comments. First, this is a good story. The screenplay--the lens through which we see the story--just needs a bit more work. My comments are aimed at helping you improve it. And as comments, you are free to accept or reject them.
I know there is not much depth to Kate's character, for I focused a lot on Mike. It started of as a love story between Mike and Kate, but during rewrites, I decided to make it about Mike. I'll add more depth to Kate's character. My problem is that it's already 25 pages long lol. It's going to get bigger and bigger.
Most shorts are considered less than 60 pages (an hour). Most producers like shorts kept to 45 pages. So by my reckoning, you still have 20 pages.

But seriously, tell the story first then go back and think how you will shorten it. That's what film editors and directors end up doing. They film it all then go back and cut it down to size. If there is any rule that you need to follow, it is don't limit your creativity in the beginning. If you keep second guessing yourself, you start to develop a writer's block--"How do I fit this in to 2 pages?", etc. Get it down first, then go back and tighten the script. Now if it pushes past 120 pages, you probably have a problem--it's more of a novel than a movie!
You got the ending at page 6? That's not good. I've got to work on that.
Part of this is because you jump into the premise of your movie too quickly. I've had this conversation with other writers in a different forum and I've had to agree. Some writing you start off with your premise to hook the reader and develop it. In other cases, you start with a teaser to hook them, then introduce the plot elements. In more classical movies, you see the story unfold gradually. This last is often criticized by modern writers because many believe that it conflicts with the short attention span of modern audiences accustomed to action movies. In my opinion, all three are perfectly valid and must be fit to the story you are trying to tell.
This will sound rather sexist. My observations and experience seem to indicate that men need the immediate action/disclosure (guts & action) while women enjoy the unfolding development (depth & emotion). The use of the teaser followed by the development and reveal (as often seen in TV) is a compromise to capture both audiences. It is why screenplays written from either extreme are often "guy flicks" (action without depth) or "chick flicks" (deep development, relationships). When you can marry both, you get a box office hit--for instance, Avatar, Matrix, etc. DISCLAIMER: None of these styles is bad or wrong. They simply have appeal to specific audiences. As a reader then, the first five pages need to hook me. This makes slow development much harder to sell. So you need to put in the teaser, which may be unrelated to story but highlights the main character's quirks.
Back to your screenplay. You jump right into the blinking cursor. While I like the sense of it, it contrasts later with the description of his room and other things we learn about his lifestyle. I would work up the first four pages introducing Kate and Mike as separate individuals. Take that stop motion split screen sequence from p.2 and develop it out a bit to show Mike and Kate in their natural environments. Give me a sense of who they are. Then focus in on his room. Give me a sense of who he is. Then go into the exchange. On the first exchange, I'd keep it short. Then I'd have Mike go about some late night activity and seem to be happier than he's been. Then I'd take a few pages to have Kate share with her friend the "weird" chat she just had. I might--if it were me--give both of them a roommate who is giving them "love advice" which they may follow to their detriment and somehow still manage to get together in the end.
And yeah, even I didn't like the idea of giving a username. I'll try to implement your suggestion.
You want the "chance" encounter to be noticeable by the audience. But I would tone down the nature of the break-up from the start. I mean, if someone approached me online saying, "I just broke up" that would be a warning sign to me. I'd have it more nebulous, "Just on wondering if anyone looking to chat?"
Have the conversation evolve into something more intimate. As soon as it gets more personal, one of them immediately has to go. It's a tease but it gives each of them something to think about. Remember, Kate is just as hurt by the break-up.
That conversation on p.5 and p.6 where Mike admits he screwed up and Kate smiles suggested to me that Kate knows Mike. Later events confirmed that. I would stop showing her responses to the audience. This is where the intercut works against you. I would have Mike type his last line then "Hey. I need to run to class. Chat with you l8r." Then switch scenes.
First, if his ex left him because she knew he was using, then when he relates his story, it will tip her off. I think you want Kate to stay in the dark as long as possible. So I would again make his comments more guarded. "Well, I got messed up with a bad crowd." Remember, this is a complete stranger so he's trying not to scare her away too. You could even have him ask his roommate for advice.
MIKE: What do I tell her? She wants to know why we broke up?
DAVE: Hell, don't tell her the truth. Tell her, "She thought I was beneath her. Her father went to Hah-vuhd."
MIKE: (laughs) I can't.
Mike TYPES: "I fell in with a bad crowd. I didn't see it. She did.

"
For your story to work, you need to work hard at keeping each of them blind to the other.
I included Dave and Justin in the screenplay to give Mike a social life. One of the criticism that I got during my first draft was that Mike and Kate don't do anything besides talking to each other. So I don't know. Any suggestions to make it more *believable*?
You have a beautiful romantic comedy set up here. You have two good guys (though I would develop Kate's flaws as well to make her more human), two well-meaning roommates, and hidden identities. In the movie "You've Got Mail" you have a wonderful example of how two people who don't like each other on one level match up on another. I'd use this anonymity to your advantage. On p. 22 the date with Jim is a wonderful idea/opportunity. Somehow his ex has a way of showing up. You need a similar foiled plan for Kate going to meet Mike.
They might arrange to meet. Kate goes with Natalie. Natalie sees Mike and decides to run interference on her own. Natalie does something to get Mike to have to leave. Kate later is disappointed. Mike is again vague and makes up a lame excuse for missing. This takes some thought but gives a bit more 'wrench' to the plot and they work it out. Because it's a short, you don't need to go overboard, just have them re-schedule. And as trite as it may seem, you can have them texting by cell phone to meet at the same spot while attending some event.
And it's okay for the audience to know that these two were dating previously as long as the characters themselves don't know. Up to the first third, I would keep it a mystery. Then I would make it obvious in the middle. Then it becomes a pressure for the audience as each time the two start to meet up they are thwarted in a comical way. Because now, the audience really wants them to reconcile. And in the end, the two finally come together and the dramatic tension is released. Yeah, it's a standard pattern in romance but it sells big. Patterns are okay, just use them creatively. Harlequin and Candlelight romances are big sellers for a reason.
I think I've to elaborate more what I really want to show. And I'll definitely check back on the dialogues. Thanks for looking into it. I really appreciate it.
Cheers!
Definitely look at the dialogues. The points that confused me are the same things that confused Ken. It looks like you did a global replace of "I have" to "I've", etc. It's a good story with potential.
As odd as it sounds, the spec screenwriter is writing a visual story not the shooting script. So what you show the reader guides their imagination. The director may have totally different views, so the script will often be re-written if optioned or purchased. Needless to say, your goal is to get it optioned or purchased. For other indies here, your scripts are probably envisioned they way you want to shoot it which is fine. In that case, ignore the comments about camera angles that apply to spec scripts and go straight to the shooting scripts with numbered scenes. Spec scripts are for selling ideas. Shooting/ Production scripts are for producing movies. [And if you dig deeper you find different formats for audiovisuals, radio plays, etc.]
Tell me a good story in up to 120 pages and grab my interest in the first 5-10 pages. Introduce me to the protagonist(s), the supporting character(s), and the conflict in the first 15-20 pages. By the end, show me how the problem(s) resolved and the protagonist(s) has/have grown and developed in their relationships as a result. Simple huh?
You've done some good work. I look forward to the next revision.