The game just isn't competently put together.
Enemies have instant reactions, and can kill you in one hit as soon as they enter the screen, even partially. This means you spend nearly the whole game looking at the edges of the monitor looking for a single pixel of someone's shoe to tell you that you have the next 200 milliseconds to shoot before most likely dying.
Enemies usually have flawless accuracy, but not always. Sometimes they do miss for no apparent reason, and there are times where you need to simply rely on getting that lucky break to get past rooms that just don't allow you to get an advantage on the opponents.
You're meant to survive despite the odds by using your dive and slow motion. The former sucks to use and the latter literally doesn't help you.
The movement on keyboard is very stiff and delayed, sort of inconsistently, too. Movement isn't as terrible on controller, but that isn't really a valid alternative - the camera and reticle stay too close to your character for the game to be properly playable when you use a gamepad.
To top it off, it's hard to actually see whether you're diving or not - the animations aren't exaggerated enough to be able to tell that with just your peripheral vision, and there are no visual or audio effects to inform you of your invulnerability.
At least the dive is usable though - the same can't be said for the slow motion. I beat the entire game without using it because it's just pointless - it lasts no longer than 2 seconds, doesn't slow time that much, and doesn't even activate reliably.
The slow down also affects your character and bullets, meaning that you'll spend most of its duration just waiting for hit confirmation, and you can't use it to dodge enemy shots or anything of the sort.
The level design is pretty samey and doesn't accommodate your painfully stiff movement.
The enemy AI is basic and passive for the most part, but with some unpredictable exceptions (they refuse to open doors, but only 99% of the time) and chaotic movement.
Enemies have instant reactions, and can kill you in one hit as soon as they enter the screen, even partially. This means you spend nearly the whole game looking at the edges of the monitor looking for a single pixel of someone's shoe to tell you that you have the next 200 milliseconds to shoot before most likely dying.
Enemies usually have flawless accuracy, but not always. Sometimes they do miss for no apparent reason, and there are times where you need to simply rely on getting that lucky break to get past rooms that just don't allow you to get an advantage on the opponents.
You're meant to survive despite the odds by using your dive and slow motion. The former sucks to use and the latter literally doesn't help you.
The movement on keyboard is very stiff and delayed, sort of inconsistently, too. Movement isn't as terrible on controller, but that isn't really a valid alternative - the camera and reticle stay too close to your character for the game to be properly playable when you use a gamepad.
To top it off, it's hard to actually see whether you're diving or not - the animations aren't exaggerated enough to be able to tell that with just your peripheral vision, and there are no visual or audio effects to inform you of your invulnerability.
At least the dive is usable though - the same can't be said for the slow motion. I beat the entire game without using it because it's just pointless - it lasts no longer than 2 seconds, doesn't slow time that much, and doesn't even activate reliably.
The slow down also affects your character and bullets, meaning that you'll spend most of its duration just waiting for hit confirmation, and you can't use it to dodge enemy shots or anything of the sort.
The level design is pretty samey and doesn't accommodate your painfully stiff movement.
The enemy AI is basic and passive for the most part, but with some unpredictable exceptions (they refuse to open doors, but only 99% of the time) and chaotic movement.