Interestingly enough, I just recently made a game that is pretty much exactly the same as this... Click on my game page and play 'Magic Mayhem' if you're interested!
Anyhow as I made a game that was very similar, I can also apply a lot of the same criticism to this. First off, I noticed that you somtimes just did not place down any wall tiles? I don't know why but it just makes passages look weird.
Something that also could have been helpful would be a minimad or an indicator of how many enemies are still around because it can get really annoying searching for one enemy that hadn't died yet.
Furthermore it would also be better to maybe get some differences in howw the floor and walls look as well as some diffenrences in enemies. Having only two types makes it very monotone very fast. Although, I am guilty of the same crime...
It is just a little bit monotone to run around the map only looking for enemies to kill. You could have improved that by adding collectables or multiple weapons to make this just a little bit more interesting.
Also, the tin man is a little bit to easy... I dunno, he just kinda doesn't feel like a threat.
I do really like the artstyle, the music fits the gameplay and the sfx are clean and good.