I played through three days, it was fun to figure out what to do with the materials, and it's nice that there's a tutorial guy right at the start too! The skeletons are also pretty tough, so I just chose to stay in the shelter for as long as possible, haha! I suppose how long you survive depends on how little amount of wood you can use for the shelter every 3 days, since it all gets wiped out by the tsunami.
For your future games, I really suggest making a pause menu where you can push a button to quit the game instead of the escape button quitting the game instantly. For many games, the escape button either closes menus or opens up the pause or settings menu. This means most players will probably quit the game while trying to navigate the inventory menu like I did.