Maybe I'm wrong here, but I always thought bullet hell was just a sub-genre of shmup. Specifically, it refers to the shmups that have tons of bullets on-screen. Wikipedia seems to agree with this.
Without traditional Shmups, there wouldn't be any bullet hell shooters.
However, talking strictly from my own personal biases, the actual gameplay is so vastly different.
When I play a bullet hell, all I see is bullets. I hardly glance at backgrounds, enemy formations or anything but the bullets, and it gets terrible repetitive for me, otherwise I don't survive.
Add to that strange multiplier and gracing rules that gets more and more bizarre to the point where it almost require a manual to figure out and it becomes so different than a traditional western Shmup.
Take for instance Raptor: Call of the Shadows or Tyrian, which have constant upgrades for my ship, evolving enemies, ground and air weapons, different environments , boss battles etc. and the experience and gameplay is is like night and day.
Granted, bullet hell shooters also often have boss battles, some only have boss battles, I guess because they contain more bullets?
I don't have anything against bullet hell shooters, I just haven't been able to find any joy in them personally, even after buying and trying most of cave shooters on my iPad.
Maybe it's because I'm a child of the eighties, and I spent way too much of my allowance on any shmup I could find in the arcades in my childhood...
For me at least, it's two different genres of games, where one is an evolution from the other.
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