Its really cute that you developed that together! :)
Regarding the game: At first I tried to leave the house to the left and wondered why nothing happened. Maybe add an arrow or a tree to make sure that the player does not try to go past the invisible wall.
Then I tried to mine but didnt get anything.... I did hold down the E-button. This may restart the mining process over and over so that I couldnt farm... When I finally noticed my mistake, the game started to make fun! But I still wondered why I lost stamina when just walking.
Grafics are retro-style and quite nice. Take a look at walking circles maybe since the head has to move up and down and does not stay on the same height.
You could polish the game more and I could see that it could become a really nice game. Maybe add minigames for mining and also let others playtest to gain feedback.
Keep on making games!!! :D I really like the concept and the game loop!