Gloss describing an entire genre of
video game, especially the top-down 2D alternate-WWII airplane sims in the arcade but a longstanding video game institution, dating back at least to
Galaga.
There are five types of entities in these games:
1) The players. You cannot shoot or touch yourself.
2) The landscape. You cannot shoot or touch this.
3) Power-ups. You cannot shoot these but if you touch them they boost your capabilities, usually in the armament sense.
4) Live munitions. You cannot shoot these but they harm you if they touch you.
5) Bad guys. Generally, if you touch them, they harm you. Your airplane, after all, is terribly sensitive. You can, and should, shoot these. Follow the genre instructions - while ammo and power-ups usually travel in a straight trajectory, these guys move. What more proof do you need of their intent to harm? Big Bad Guys, which usually require sectional destruction are a subset of this category.
Many contemporary gamers long for a gaming experience replete with neutral and even occasionally benign moving entities, and some go so far as to play games without any shooting whatsoever! While this gloss also applies to any member of the
FPS genre, it is possible that the path of the aforementionned gamers is worthy of further investigation.