Also some info on foods in case you're too lazy to read through the comments to find on your own: Broccoli slightly increases your max stamina, Burgers slightly decrease your max stamina, and Proteins have no effect on your max stamina
This is probably obvious but just in case, if you have no energy, MAKE SURE that you have enough coins to buy food. If not, then the game will say that you are bad at spending money and will basically erase your save data.
i found a glitch: if you hold up and down arrow keys at the same time and then press left or right while still holding the keys, you will move faster than usual. (this only works with horizontal movement, not with vertical movement and this will not work when youre in a battle)