The PC version of Space Marine fundamentally fucked up the gameplay -- the execution system works differently (and worse) from the original console release, and nobody has ever talked about it somehow.
Alternatively, it's possible the game always sucked and I had the only good version of it due to a unique bug on my 360 disc. Like, that shit ain't the same way it was on my 360 version. I checked. It's different.
Space Marine requires the player to use special "execution" moves on enemies to regain health, like DOOM 2016, but years before that. A key detail is that you are not invulnerable while you do the kill animations. This brings us to the key difference that makes the game dookie on PC:
On the 360 version, or at least the particular disc I have, you cannot outright die during the animation. You can still take damage, and you can still take so much damage that it ends up being a bad choice, so there's still a worthy risk-reward consideration, but you can't outright fucking die during the animation.
It was still totally possible to die literally seconds after the animation finished, such as if you regain less health than you lost during the animation, but the animation had to at least finish.
This created exciting battles where you'd be basically riding a wave of execution moves to keep yourself alive while under constant assault. Like, you're barely keeping your head above water, chaining from one "safe" point to another -- just gotta stun somebody and reach them before you outright die and you're secure for another few seconds. It felt really cool actually.
On the PC version, you can and likely will die frequently during the kill animations, making it shit. It's just annoying shit now, and feels super cheap and unfair, especially since the kill animations have different lengths, and you can't choose. Best is when you die right before it's about to finish and give you the health you wanted in the first place.
This doesn't even start to become too noticeable until the second half of the game where the Chaos dickheads start showing up, and the little renegade guardsmen absolutely light your shit up with their rifles even on normal -- they're scarier than the chaos marines or the demons.
And the protagonist has to drop some fucking Dove chocolate-ass "live-laugh-love (The Emperor)" line every time he dies, making it take just a little bit longer than it needs to to get back into the game.
With this change (or bug, or lack of a bug, whatever causes this) the second half of the game (which used to be my favorite part) goes from being a solid action beat-em-up affair to a 3rd-rate 3rd person shooter with no cover mechanic against enemies that start Gears-of-War-ing your ass.
If this is how the game was always supposed to be, good god what a turd. If they changed the game, good god what dumb-asses. Did I seriously get the only good version of the game years ago, due to a unique bug on the 360 disc? I have no clue, it's so fucking weird.
It's also worth noting that each frame is an opportunity for player inputs to be registered by the game, so for any sort of game where tight reactions are an important part of gameplay (which is many -- particularly fighting and other competitive games), higher framerate can directly translate to more responsive controls.