Hey thanks for playing again and sorry for the (very) late reply.
I'm actually using vectors for projectiles, however it's all overcomplicated by the fact that i use 2x1 tiles, which are also used as an easy way to check for collisions. The characters movement is just from tile center to the next, so diagonals seem faster, but actually are the same distance technically (time to move from A to B is the same in the calculations). Something about it has to change though, i agree.
Holding the mouse is something i already implemented briefly, but it was really buggy. It led to some weird behaviour in some cases. Similarly the hold mouse down to keep attacking was also bugged (a single click would trigger the attack twice :( ).
Glad about the positive feelings inbetween bugs and lack of QoL though!