If you've found the PC version of Vanquish much harder than you remember, you might want to try lowering your framerate.
Vanquish wasn't an easy game when it was on PS3 and Xbox 360, but there are reports that the new PC port that launched yesterday is even harder. As it turns out, if you're taking advantage of the option to raise the framerate from the 30 fps the console version was locked to, you're making it harder on yourself.
The issue is highlighted in two gifs from NeoGAF user Wesker, who shows the difference in damage rates. Wesker wrote, "If you lock the framerate to 30FPS AR mode will activate after 6-7 seconds of taking enemy fire. If you're playing at a much higher framerate, like 144FPS, it will activate in just 1-2 seconds." AR mode is the slowdown feature that kicks in when your character gets near death.
The first gif shows the game at 30 fps, while the second is running at 60 fps. Note how much faster the player reaches critical health levels in the second gif.
The issue has also been mentioned in Steam reviews and on the game's Steam discussion board. Sega has yet officially confirm the bug, but until it is addressed, you can always set your copy to run at 30 fps to avoid it. If you've experienced this issue, let us know in the forums!