and I can say right now, they wont work on late-game enemies.... not if I have anything to say about it anyway, hah.
I don't think it should be impossible. It should be extremely risky- suicidal even, but like... In a lot of bullet hell games, your fire rate/DPS/whatever goes up if you're really close to the target (as a reward for the risk). I think that's a really fun concept to have in the game, but I do agree it shouldn't be making the subweapons unusable for most people. It would have to be a mechanic that just is always in effect, or an upgrade like "damage increases by up to xx% as you get closer" or even a ship hull bonus of some kind.
Well, to put it a bit differently.... nobody will actually USE weapons like that.
After watching 10 squillion videos of people playing bullet-hell type shmups, one thing I've noticed is that nearly all of them stay as far away from the target as they can. Only the best of the best will get close, and even then, it's just outright not viable against many enemies, often working only if the enemy hasnt fired at all yet. In this game, that's not going to work, because most things will start firing before you get anywhere near them. Even jumpscare types fire long before you get THAT close.
Now, granted, it depends on the enemy type. But as I said, I havent gotten nasty with these yet, so the "difficult" foes havent yet appeared (they're about to though; I just updated with the first two of this sort). The tougher ones on later floors just wont be vulnerable to super-short-range weapons, and even if they are... these weapons are just pointless if nobody uses them, which makes them a waste to have in there when something else could be there.
To give an example of another game doing this, look at Isaac, and the "Number One" item. It gives you high fire rate, but makes your range super short. As such, nobody ever grabs it. The only time they end up with that item is by sheer luck, if Curse of the Blind (makes all items look like ? marks) is active and an item just happens to be that one, so they grab it without knowing this. Other than that, never used. One of those "why is this even in here? They could have put something interesting in there instead" sort of things. We'd like to avoid having this happen in this game as much as possible.
That's not to say there wont be difficult and risky items, as I'm hoping that some like that can be made. Risk and reward and all that. But they need to be difficult and risky in a way that isnt totally absurd, or they just become pointless to have.
....also, the range on those super short range weapons was REALLY short. Like, your ship had to pretty much be TOUCHING the enemy in order to make contact. Even I dont get THAT close to enemies when attacking them.