The game is both cute and scary, it's pretty nice.
It would be nice to have a more 'casual' game mode, one where you can save the game at the bed or something, everything else would still be there, but maybe as a penalty you would get less money per crop, forcing you to play for longer, but without the threat of losing everything and starting over, only losing a bit of progress or money or w/e would be balanced.
Or you could even have it become a rogue-lite game, where the character is basically stuck in a loop, forced to experience the same horrors over and over, and only leaving the island might end it.
Make upgrades be 1/25 or 1/50 instead of 1/10, and more expensive for the higher levels, but make them and coins permanent, allowing you to slowly progress further, but always being forced to suffer a horrible fate over and over until you eventually succeed.
Either that, or keep the upgrade system the same, but add a skill system where you get better at doing things as you keep doing them. This seems pretty hard to make and balance though as it would need to implement a whole new system into the game, especially since it would 'force' players into grinding certain skills instead of simply playing the game as was intended without proper balancing, but well done can add an extra layer to the game, where the player can rush certain upgrades in order to maximize EXP gain for certain skills. You can also go the inverse route, where upgrades are permanent, but skill reset each run, making players get better over time every run, possibly grinding some skills for the best effect early-game in order to give them an advantage mid or late-game.
In the end it's up to you if you want any of these changes, just some ideas to help you decide. The 'long term' gameplay mode would also help you add more things to the game, since once the first goal of getting a boat is achieved, you can re-use the same map and add some new things, giving players a new goal since the boat didn't solve the loop problem.