Yay, well done! Finishing any game is difficult, just as everyone ever involved in game development has said.
It was fun to watch the animation, and to have a reason to reach the end of the maze. There's also something satisfying in navigating a maze with arrow keys rather than following it with my mouse - my wrist tends to jump occasionally and all hope is lost. I never had any problems with the movement or collisions or anything, all worked just as expected.
And then criticism. The mazes themselves don't really seem to get harder based on the difficulty chosen, they just get longer. Granted, this is a game about a speedrun, but the extra paths were rare and too short to mistakenly travel down. Of course, if this were something you intended to spend more time on, practice integrating sound [really I only see background music fitting in here] would be great. You could also try playing with the maze design; maybe give it a bathroom or office theme? I don't really have any suggestions because art isn't my thing, but anything to take it beyond the black and white would be fun to mess with.
So yes, good collisions, solidly made, complete, congrats! Keep making games and making people play them.