Hi there ! Firstly, thanks for playing and taking the time to write this commentary, really appreciate <3
I can't disagree with all the design problems you describe, especially some UI about HP inside the game, which is obviously the thing i should've taken more time on, but i had to do it that way, mostly due to a lack of time :p
Better signs & feedbacks could also help understand without explanation which orb to use on which enemy and i may eventually go back to this, but i'll have to fix my whole collision system before i do anything else on this game, it ended up pretty broken in the end due to rush code :D
Outside of that, i'm sorry you had this bug on wave 14, and i know the difficulty curve is kinda slow, but i feared that many players would've run into troubles with how the game controls (it's a bit out of classic genres ^^) if i did hard waves fast, so i decided to slow it down, maybe too much tho.