Thank you for the reply!
What I mean by non-existent weapon variation is that not it doesn't have enough. But rather all weapon behaves very similar. That's why I said every weapon is like autocannon. Their stats and method to use is not different enough to warrant player using different weapon. Like vulcan and gatling is basically the same weapon, only different in minor stats... even both of them are quite similar to autocannon, just with windup in the beginning. Smartgun is also like autocannon, but at least it different enough in the way you aim the gun and how it homes to the enemies.