Each run is different
During your journey to find out about the source of the apocalypse you fight a lot of crazy machines that took over the world. On each run you will come across powerful upgrades and weapons to customize your character. Each weapon plays significantly different and has strengths and weaknesses. You will find out which power ups fit your style of playing.
Enemies with features
Not only the world and the power ups are procedurally generated, also enemies are spawned randomly. On top of that they can evolve mutations that make them even stronger. Watch out for the next boss fight, it wot't be the same as last time...
Unlockable characters
If you are doing well, more fighters of the rebellion will join your team. Maybe you are not into dual wielding machine guns? You should try out another character with a futuristic plasma bow, stealth features or even a melee one?
Alone of with your friend
Let's be honest, slaying your way through a ton of metal scrap is the best way to spend your evening. But even better: you can do it together with your friend. Enjoy local co-op. But don't catch a fight about who will get the next upgrade...

Minimum:
OS:
Windows 7+
Processor:
Intel Core i5 or equivalent
Memory:
8 GB RAM
Graphics:
Nvidia GeForce GTX 970 or AMD equivalent
Storage:
2 GB available space
Recommended:
OS:
Windows 10
Processor:
Intel Core i7 or equivalent
Memory:
16 GB RAM
Graphics:
GTX 1070 or AMD equivalent
Storage:
2 GB available space