Hey, good job! Honestly pretty fun. Not bad for your first game!
The sound design is good, nothing is too loud or too quiet. Sound effects and music both pretty well done!
Here's my feedback: I could never get 15 assassins, I wasn't sure how to achieve that. However I think it's cool as a main goal.
I think it's kind of pointless to 'defend yourself' as it tells you to, when you are invincible. Maybe a cool idea would be to have a defense point? Like maybe there are survivors of the crash around the helicopter, and you have to defend them. Otherwise there's not much motivation to killing the guys.
I like the font choice.
Overall nice work here!!