Skip the risky crack. It often goes on sale during Steam seasonal events, and the official version gives you access to the Steam Workshop , which has thousands of incredible fan-made maps and gear mods that essentially double the game's content.
The gunplay is tight and punishing. You have to manage rules of engagement, non-lethal vs. lethal options, and meticulous room clearing. If you run and gun, you will die in seconds.
It is important to be clear: downloading a "crack" for Ready or Not is a fast track to compromising your PC. Sites offering free cracks for modern tactical shooters are notorious for bundling into their installers.