I like the mechanic of the snake speeding up for certain foods, as it naturally increases the difficulty as the player survives, and makes progressing through the stages faster. A possible improvement may be to drop a normal food alongside the speed-up food so that the player has a choice between getting more points but enhancing the difficulty in return vs. going for fewer points but retaining more control. Controlling the snake becomes increasingly difficult at higher speeds, especially when performing tighter turns. Another thing that could be added would be a speed-down food, where the player suffers a point penalty in exchange for lowering speed to a more manageable.
It was a good idea to have a different sprite for the food types as it prepares the player for a potential speed increase; some sound effects would help distinguish them further.
A potential issue is that food can spawn on the same tile as the snake's body. I didn't survive long enough for it to be a frequent problem, but it was slightly confusing the few first times that it did occur. Incidentally, did you include a special outcome for when the snake reaches it's maximum length?
Overall, it is a simple and fun reproduction of the snake game, and is a great start for your journey as a game dev.
A novel interpretation of a classic brick-phone game.
P.s. My final score was 450.