Red Rage combines a gory zombie shooter using simple, easy to master controls with a 'red only' art style. Players will fight on a variety of maps and fend off zombies to reach higher scores and in turn unlock more exciting weaponry. Zombies will attack in waves and sometimes players must be willing to fight in the dark with only a flashlight to guide them. A simple UI makes for cinematic, heart-racing gameplay with breaks only long enough for a reload.
Mature Content Description

The developers describe the content like this:

Contains frequent extreme gore and blood when killing enemies in the game. Players use a variety of firearms to shoot zombies whose limbs and head will dismember on being killed.
System Requirements

Minimum:
Requires a 64-bit processor and operating system
OS: Windows 7 64bit
Processor: Intel Core i3-8100 or equivalent
Memory: 4 GB RAM
Graphics: NVIDIA Geforce GTX 560 Ti
Storage: 8 GB available space

Recommended:
Requires a 64-bit processor and operating system
OS: Windows 10 64bit
Processor: Intel Core i5-4590 or equivalent
Memory: 8 GB RAM
Graphics: NVIDIA Geforce GTX 750
Storage: 8 GB available space

https://store.steampowered.com/app/1457930/Red_Rage/