Interesting twist using the skin of a snake game and turning it into a dungeon crawler using point value doors. Enjoyed the prototype!
I didn't encounter bugs in my brief playthroughs so my feedback is largely cosmetic:
Consider adding more detail to your instructions intro:
For a player who may not have ever played snake it may not readily be apparent how snake games work, much of it is left to be implied by fore-knowledge of how it generally plays.
For a player who hasn't any experience with a dungeon crawler, it can be easy to miss that the player can navigate back to previous rooms and continue to grow the snake with easier room layouts instead of staying on the new one.
The concept of accumulating exp also should be further explained as the game assumes the player would understand it's based on the snake size when you die rather than some other accumulating value.
QoL and accessibility options to consider:
The font and presentation of door text could be improved for better visibility. Multiple labels for the same number appear on each door with parts cut off for them. Consider removing the trimmed duplicate numbers and utilize more of the white door space to increase the size of a single number label. Consider also adding some text label to direct a player to understand that the white space on the wall IS the door to begin with.
Lastly, working in a means to modify snake speed could be a consideration for players with slower reaction time when changing movement directions, especially when approaching a wall.