It took me some time to understand the controls, I think that it comes down to how the maze looks. Everything is very similar so it's hard to understand what you did after you pressed a key. Some kind of transition and more diversity in the look of the maze would help for sure.
It's pretty hard to track where you are and where you already went. You could add some kind of trail to help the player.
If you want to reward the fastest players you could add some kind of score to each creature and each creature you get fills a "combo" gauge that gets depleted when you don't kill anything. You could have some kind of score that represents the most optimal path in the maze.
Loved the audio track :)
Congratulations !