This is very cool <3

It looks, feels and sounds great :D

Bugs:

Some elements (main menu, bottom bar, right-click menus) glitch out after resizing the window

The shapes tool leaves flashing lines behind where you were dragging it (seems to fix after centering the camera)

The tutorial button doesn't seem to work. If it's not implemented yet, maybe grey it out?

Suggestions:

Click-and-drag to select multiple objects

Removing the 'Kill' option on set pieces (it looks a little weird)

Ability to zoom out and view the whole map

Adjustable eraser size (it takes a while to erase lots of lines)

Ability to measure distances between corners? (I know some people who prefer this)

Including a list of the hotkeys somewhere (or maybe in brackets next to the action in the menu?)

Add some more hotkeys, e.g. delete a token, cycle skins,

Sorry for giving loads of feedback, I'm just so excited to see where this goes - I might finally be freed from roll20 :P