Very creative game! Took me a few levels to figure out that the snake's body blocks it with its tail specifically being the win. This can easily be circumvented by having the head and the tail be a slightly different colour then the rest of the body. The level design in the early stages can also accomodate slightly more for this, making a few levels with only one fruit (or one of each type) at most, as even three fruits in an early stage can be a bit too overwhelming. Though the difficulty curve definetely allows the player to catch up, and makes sure they got all the knowledge they need by the time the game escelates. If I were to improve anything else it would be to touch up the sound and polish some of the visuals when getting a fruit or beating a level to increase the excitement of progressing or having your snake change (you can take inspiration from how games like Baba is You for example have all sorts of small visual flair when you interact with its mechanics).
Besides that, the visuals are great, the grim background and the dull colours of the temple/dungeon definetely complement the game's ancient tone, and the use of apples and rotten apples as what shrinks and grows the snake is a fun visual design.
Best of luck!