Lets clear this up. The game is still being developed and it has currently 10+ hours of gameplay already. It can be a lot more if you try to see all the paths. The 70+ hours refers to the original version, the version of the game being released in Brazil since 2018, and its on Episode 83. The global version is a remake, with 4k images instead of HD, animations, musics and sound effects (like moans etc). Its like a new game.
Buying the game now gives you access to the the content already in the game, and all the future updates.
If you don't understand something, please share and I'll try to explain.