Yo, thanks for checking out the game! You're right, the ending does seem abrupt, I've had more than one person complain that they aren't sure what happened and it's true, I didn't write it in. It's not a very happy ending, they're supposed to all be dead aside from you and the one other person who decided to stay. But time constraints led me to kind of forget to elaborate on that. I'll be doing so once the jam is over, though.
Regarding military stylings, there really isn't too much going on aside from Sergeant just going by that nickname, even though you can choose to use a different name later. I didn't want players picking a silly name at the very beginning of the game because I felt that might ruin things, which is why I give you the option to do it later. I came up with the backstory that made the nickname make sense- it's the character's rank before they got to participate in the program. But that's about as military as it gets- the rest of the crew isn't meant to be military.
Also, what do you mean by "time discrepancy"? I can certainly answer any questions you have if they aren't answered in the optional document you can download. It's just a text file that explains some of the reasoning behind the names and other details.