Manga Studio is a good program, and designed for works intended for print. I know this because I have and used Manga Studio 3 with my own wacom tablet.
Before I critique your work, I'm going to critique your art direction. But before I do any of that, I'm going to tell you a bit about myself. I am a visual communications designer with the skills and knowledge for comics and illustration. My entire illustrative direction has been geared behind comics and graphic novels. I am professionally trained, though I don't have any work that I can legally show you. So I hope when you read my crits, you realize I know a little about where I'm coming from, and take my wisdom to heart.
First, I will critique your style choice; Manga. I love manga. I really do! My favorite manga is Battle Angel Alita, and one of my favorite animes was Akira. Manga utilizes a very unique story telling mechanic that is very person, and connects the reader to the characters moreso than the world they inhabit, on average. It's very stylized, and has many pitfalls and tropes that should be handled with care.
Both of the artists responsible for the comics I mentioned are also accomplished illustrators. They can craft the human body with precision and care, as well as a landscape or cityscape. They incorporate the environments of their world into the story. Manga, in the generic sense, suffers from a very narrow focus. Scenes focused on heads stacked on shoulders, where the perspective of the viewer is looking in at a slight angle. You have 5 panels, and this phenomenon has occured 4 times within that span.
In my education in design and illustration, early on I was inspired by manga artists. I was always reading a manga, and even showed some of my teachers what I hoped get into. The kind instructors cheered me on. The very toughest instructors, and the ones I learned the most from, gave me invaluable advice that frustrated me then, but I'm thankful for now; [em][strong]"Do it right before you stylize."[/strong][/em]
Manga is a stylized form of art. It uses very identifiable features in its characters. Artists and illustrators that can only use the manga artform make things harder for themselves from a visual appeal standing, and ultimately limit themselves on the professional level. When you enter school, teachers (worth their salt) are going to tell you to draw the human figure, and learn anatomy. You're going to draw the skeleton, you're going to draw naked people, fat and skinny, bald, with long hair, tattoos, piercings, with a variety in value (shade) depth. These people will be standing, kneeling, holding things, etc. The work you do emulating the scene you see will be one hundred times better than the stylized form you've fallen for. Even just one year will be enough to put you on the right path.
[summery]
To finish my critique of your art direction, let me end in summery. Manga and it's styles are [em]fine![/em] But learn how to actually draw the human form and the world the form surrounds before you stylize. You'll be a much better manga artist for it.
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The critique of your script; This is a little easier to learn than drawing, so I won't talk your ear off about it.
I didn't read your comic.
"What?! Then how can you critique it??" I can already hear someone (maybe not you, maybe it is you) bellowing that out on the other side of their monitor. It is because I did not read your comic that I can offer a valid critique. Let me explain.
(Actually, the paragraph below involves [em]typography[/em], which is a HARD topic to tackle, so I will stay broad and keep it as simple as I can.)
Good writing in literature has a few mechanics going on behind the scenes that many people aren't aware of. If you open up the book of any ol' New York best seller, you should find that the words are easy to read, and your eyes don't derail from their journey across the page. It's not uncomfortable to read, and the flow of the type, as well as the type choice. In comics, text is competing with your illustrations.
It may help to think of your text as a shape. Blur your eyes, and look at your text. (tip; print out your page and do this. Your monitor tells you lies, but a printed document is all truth.) If it is a heavy dark brick, but the illustrations are soft and light, then the contrast will be jarring. Also the content of your words; I can tell you have a lot you want to say with so few frames. My typography teachers always told me that when writing something out, 13 to 14 words across was usually the most you ever want to use. More than that, and it becomes exhausting for the reader, and they tend to lose interest. A growing problem today, since everyone has so many forms of media going on all at once.
[strong]Immediate changes[/strong] to your comic that I think you'd benefit from? Either make value contrast on your illustrations more bold,
or and lighten up your text. If your font weight is on regular, switch to "light." Edit your own words down so you say the same thing with fewer words. You'll have to play the editor. If there is a melodic value to the word choices you made, to need to then spread them out over more illustrations. This means draw a few more scenes-- not a lot! Maybe another page. Draw to much for a scene, and it becomes problematic. Well, since this is just an exersize, you could probably get away with up to 2 additional pages fine.
[strong]Art skill critique;[/strong] you're practicing, drawing, and these are all good things. I remember when I got my first wacom and photoshop 7. Mm, those were the days.
But remember that Manga Studio 4 and your tablet are just tools. They are not a supplement for skill. I suggest drawing your friends. Blur your eyes, and look at the value (another word for shade) on their faces. Don't be afraid to draw things you've never drawn before. (You're going to have to in school. Get a head start on it now.) Don't be afraid to exaggerate with your values either. On average, people are either overly conservative with their values, or overly abrasive. You are conservative, and seem to only be using line. Don't be afraid to put the ink down, and make an area a fat black blot, rather than skim the region of value with bold strokes. Play around with value more.
Don't be afraid to draw in eyes behind hair (frame 1). It's hard stuff at first. You see shapes at a glance, but it's actually a series of strands. If you wanted the eye to be concealed by darkness, again, push your values. Right now the strokes imply a value of dark somewhere at the 50% range. I should be able to see the boys eye, but it is instead missing.
[strong]Reading Homework;[/strong] assuming you're serious about getting into school in a couple of years for this kind of thing, you would be ahead of the class if you did some reading from professionals. Three books that I love, I think will help you immensely listed in reading order.
Understanding Comics by Scott McCloud [http://www.amazon.com/Understanding-Comics-Invisible-Scott-Mccloud/dp/006097625X/ref=sr_1_1?ie=UTF8&qid=1293278199&sr=8-1]
Making comics by Scott McCloud [http://www.amazon.com/Making-Comics-Storytelling-Secrets-Graphic/dp/0060780940/ref=sr_1_1?ie=UTF8&qid=1293278226&sr=8-1]
Perspective! for Comic Book Artists [http://www.amazon.com/Perspective-Comic-Book-Artists-Professional/dp/0823005674/ref=sr_1_1?ie=UTF8&qid=1293278088&sr=8-1]
I recommend buying these books, and never letting ill come to them. I still reference these books after all these years.
I've talked your eyes (yes, eyes) off enough.
I wish you the best of luck. You'll always be learning, and as long as you keep pushing yourself, this time next your you'll be 100% better than today. Take my critiques to heart, because they are only meant to make you better.