Ah no need to apologise, every game has teething problems! It doesn't give any information - whenever I click on a save slot the game just shuts down. I'm still able to play right through the game though..
Thank you so much for reporting this! This is the other developer. If you could, do you think you could make it crash again, then go to /Monstrata.app/Contents/Resources/autorun/ and send us the log.txt? It would really help me replicate your issue, and hopefully fix it asap!