A few things I notice straight away: you should always place a space after any punctuation, not just periods. Also, use ellipses (...) sparingly, and only ever use three periods in them. You should also press enter twice for line breaks on these forums, so there's a visual break in text.
i.e. Jacob Johnson liked the following things: board games, pickles, tricycles...and some other stuff.
Jacob's love of other stuff influenced the path of his life intensely, which is why he became a scientist, eventually being appointed Executive Scientist of the XCOM Project.
Other than a few little mistakes, it's clear you put a lot of effort into it, you paint a decent picture of his personality between dialogue sections and synopsis, and you have a lot of directions available when it comes to writing the journals. The only major thing I see when it comes to the creativity of it is that the first section is from the POV of who I presume is an XCOM recruiter writing a report for the Commander, and it seems a little iffy at times (a recruiter generally shouldn't be pausing on paperwork, he should be confident of what he's reporting or not mentioning it). This isn't an issue now though, since you'll only have to write as your character if you're accepted.
The best thing I find to do with writing is to just go for it first, get all the creativity onto the paper, and then run through it again to make it proper and pretty. Practice makes perfect, you may find things that can be improved the second time you read it. Another good tip is to preview (by pushing "More Options", if you didn't know) before you post future long writings like journals and see if it looks like it would be easy to read or skim so it gets more attention.
