Thanks for the compliments and feedback! It's funny you mentioned Heartbeast's videos, because I actually watched a lot of his stuff when I was first learning GameMaker Studio. Unfortunately, I wanted to figure out as much of this game as possible on my own at this point, so I only referenced tutorials I'd seen before for occasional stuff. I also never attempted a platformer before this, so needless to say it was a bit of a learning experience in that regard particularly :P
Sorry about the installer. The only options I was given were for that or a .zip file, and for some reason it wasn't letting me upload the whole .zip file. I likely could have figured it out, given more time, but I was close to the deadline at that point. I plan to use a .zip file next time, though!
I'm also sorry to hear you had so much frustration and difficulty with the game. I did a lot of testing to make sure it wasn't too hard, so I'll admit I'm a little surprised. I'll try to fix the jumping in the post-jam patch update, but I can't make any promises for practical reasons, unfortunately.
There actually is a sound effect when the boss takes damage. Maybe it was drowned out a bit by the background music or bat swing sound. Again, I'll see what I can do about this in the update.
I am glad to hear you liked the game overall! Rest assured any feedback I'm not able to use when patching this game will be kept in mind for the next one. Thanks again!