Can you really ever have too much hardcore?
I'm a big fan of boomer shooters, and I also love fast-paced shooters. I've only played first-person games since I was a kid; I grew up playing Doom 1 & 2, Duke Nukem 3D, Hexen, and Wolfenstein3D. Now I'm 30 years old, and I played lots of first-person shooter games, including those similar to this one, but it's too hardcore. Yes, it's too much. A good game doesn't push you to the limits and gives fair challenges to the player. Dodging enemy bullets with 360 degrees is pure luck. This is what I call unfair. This is just annoying.
Try the Demo on Steam, it seems like an all around smoother experience. More linear, quick to figure out paths where you don't get surrounded.
I'm about an average skill gamer with maybe above average aim (I rarely do very well in PvP games) and play all my games on normal/medium difficulty and still found the demo very fun and not frustrating at all. Levels are so short that you lose at most about 3 minutes of progress, which helps make it not as frustrating and the game's nature gives you that drive to perfect your run anyway, so even if I cleared it, I would try again until I felt I did my best.
I've only ever seen videos of the Itch prototype, but it's very clear to me that there's level design in this that will slow down the pace and push you into the defensive. The Demo on the other hand is made in a way that three, four good shots can defuse most rooms in few seconds before any of them can fire a shot, either by killing them or kicking/blowing up barrels. And when there's a big horde coming up, there will be an SMG guy placed right before that so you can deal with that. Your forward momentum is almost never hindered.