Like any other Devil May Cry, you need to upgrade your skills and improve your combat to experience all the cool and satisfying moments the game has to offer. Like any other game ever made this game has its own secrets to unravel, but instead of just shoving them at your face or requiring little to no experience to find. DMC V requires you to get good at the game if you want to find out what those secrets are. One of those secrets is that you can beat the whole game in just the prologue, "If you know what you're doing and can take on a level 80 boss as a level 1 character because that's how Capcom Mafia works."
It all starts in the Prologue
In the Prologue, you play as Nero as it is revealed that his demonic arm is torn off by a mysterious figure, which makes Nero go mad for revenge. All this on top of Nero's first encounter with Urizen is meant to show how much powerful the final boss is and Nero needs a lot of skills and upgrades to beat him. But, It's possible to still beat him and end the threat before it even begins. Just to make things clear, You have to be a highly skilled DMC player to pull this feat. If you really have a lot of time to invest just to prove that you're the best of the best then be my guest otherwise just play the game, get all the upgrades and come back to finish off Urizen. Even the Prologue mission tells you that Nero is outmatched.
You need a lot of patience and skills for this one
But if you're really determined to see this secret ending, it's recommended to fight on the Devil Hunter Difficulty. The best thing to do in the boss battle is to keep moving and avoid anything Urizen throws at you. This may sound like a usual tip but keep in mind that the whole point of this boss fight is to show you how powerful Urizen is and he will do all he can to keep you away from him. To go into the damage phase you have to destroy crystals that protects him. The crystal not only shields the boss but also has attacks of his own. So just try to remain as close to him as you possibly can and do as much damage as you can to the crystal until it shatters. Doing this will leave Urizen vulnerable for a short amount of time, Try to do as much damage to Urizen as you can before he regains consciousness. He'll conjure another crystal so just repeat the above process again until you nail that final blow. Once Urizen is defeated you will be greeted with a humorous ending and a trophy that you can brag to your friends about.
Once you're done beating Urizen in the prologue, try beating him again on Dante Must Die mode. That will be a real challenge worth bragging about.