The very idea of racing with Slender made me want to start the game. I was expecting something more cartoonish, as I almost saw it as a mix with Mario Kart haha! But I understand your desire to preserve the original atmosphere. I loved the tower area. I rode it with the music from Initial D in my head (Deja Vu!!!), with the epic jump at the end, haha. It was superbly staged, like the jump between the two trucks.
I had a lot of fun, even though I never managed to get more than 6 items because I was going around in circles and Slender was right behind me: the slightest mistake and it would be game over!
Well done!