This piece contains spoilers for several Earth Defense Force games.
Emotions are complicated. This isn't something you need to be told by a psychologist, it's something that as a human being you intrinsically understand to be true. The advantage of complicated things is that you get to explore them, really dive into them and dissect them. Maybe you'll never understand the exact science behind it, but getting to see the potential for each individual feeling is something that gaming does very well. After all, with an interactive medium such as this we can become another person and inhabit their heart, see what they see and feel what they feel - to a certain degree, anyway. Inevitably your own experience will influence just how much you can empathise with any story, but sometimes even if you haven't experienced something first-hand, maybe going through it in a game helps give you an idea of the real-world emotions that come with it.