It can be quite frustrating. As I understand it you loose 5% off every skill when you die. This is hardly noticeable when you are starting out but can become an issue when your skills are leveled up.

Spawns at night go way up it seems. Any work you do is going to make some noise but using an ax or pick on anything makes a LOT of noise and draw every spawn in a 100 meter radius making mining at night a particularly wild time, Building isn't quite as bad but will still get you an above average amount of attention.

You can call the bosses up again as long as you have the sacrifice and will get the same drops but if you don't need or want those drops there is no compelling reason to do so.

It can be a hard game. I think a main reason for this is it requires a large amount of player adaptation and not as much character optimization, something that isn't that common in games in my experience. It also requires you pay attention. Forgetting to eat has been a fairly common root cause of death in my time playing.

Good luck with your game and remember to have fun.