Thanks for playing and for the feedback! I was able to get 3 more versions up before the deadline, so there is a much newer build than the one you tried. The final version has player HP, a loss condition, and several last minute bug fixes. Please do give it another try if you get a chance! Thanks again!
Edit: Regarding the keyboard layout, unfortunately the HTML5 builds using GameMaker would not work with the Left-Shift key to cast, which led to the addition of “C”-to-cast for those that don’t have a middle mouse button.