What kind of person is the main character? While it may not be necessary to know whether he's a insane braniac out for world domination or a shy little girl with freckles and a lopsided ponytail, it is however unclear what your main character is. He or she could be both, none or all other possible options. Fleshing your character out a bit more is always nice, so the reader can imagine the scenes a bit better.
Only exception to that suggestion is when you want the reader to be your main character. However, those kind of stories are beyond your current skill set and are ridiculously hard to pull off.
Kid walks on beach, sees 'mon, goes to sleep, wakes up, enters bad guys' hide-out where growth hormone experiments are conducted, saves the day and ends up catching one of the test subjects.
While generic and bland plots are written by the dozen, I suggest you start thinking about crazy story plots. Maybe the chief scientist working for the bad guys is the main character's uncle. Be creative, variate a bit.
Exactly 1 line of dialogue, and even then not good enough to warrant a decent grade.
People communicate for 10% through speech; 90% is body language. However, since we rely on text here, let speech at least do that 10% of your story. Dialogue tells us a lot; it tells us if the character has a speaking disorder, if he is shy or unintelligent. Use it.
Grammar, spelling and punctuation gives structure to your story. And yours sadly had none. I could go on about what was wrong, but it would be more efficient to read: << How to write stories >>: Grammar guide.
Since you had next to none of this, I'll explain it to you.
What would you as reader rather read?
A: As Andy reached the tree, he sat down beneath it.
B: As Andy reached the moss covered birch tree standing in the middle of the fork in the road, he cleared the grass growing beneath the white barked tree of most of the visible dirt so that it wouldn't stain his khaki shorts and sat down in the cooling shadow casts by the tree.
Detail is nice to read, informative to know, and suiting to the mind.
This section suffers from the general lack of quality in the other sections. So, I won't hold this one against you.
A 4,000 character story for a 40,000 character Pokemon. Even you can do the math.
Yes, I know it's your first story, and I know we've got to be lenient to starting writers, but I assume you agree with me why this is a non-capture.
Sorry, Cloyster was not captured.