FromSoftware's Dark Souls series is renowned for existing as some of the hardest video games to exist. This franchise is full of heartbreaking, rage inducing, deeply immersive ARPG content that will upset you, but keep you sucked to it like a vacuum. They are only for the hardcore gamers, and will ruin anyone's day if they just want to have fun. Nevertheless, this game series thrives on and has quite the cult following on the internet.
For anyone who has played an NES, SNES, or Sega Genesis before, you will know that most of the games available for these platforms were platformer games. Super Mario, Sonic the Hedgehog, Contra, Altered Beast, Ninja Gaiden, etc. There is a recurring theme within these games; you go through the level, get through enemies, and fight a boss at the end of the level. That was the standard for those games. Dark Souls is known for bringing back difficulty in games. Demon Souls was difficult, but not nearly as much as any of the Dark Souls games.
Dark Souls follows the same patterns as any of these retro games. Dark Souls has levels through out, with a boss at the end of each of them. You beat the boss, get through to the next level, and play that level. Rinse, wash, repeat. This isn't a bad thing. In fact, it makes the game a little more playable knowing that the next area is that much easier to find, even if it is hidden.
This might shock you if you are a Souls player. Bloodborne and Sekiro: Shadows Die Twice both follow this idea too, and most of the souls-like games. If you are interested, check these links to try them for yourself.