I've updated to use a scaling factor instead, which defaults to 2 (I think the same as the screenshots, although obviously browsers are handling things a bit differently here). And have hopefully fixed the UI bugs you found (thanks again!).
Awesome, looks beautiful now, and also the mouse works! I don't really need the mouse, but I tested it out to see, and noticed there is one issue: You have to move the cursor after entering firing mode for it to register your proper line-of-fire, which otherwise defaults to targeting the origin (yourself). I discovered this because I'd be quickly moving the cursor to targets while firing, and if my cursor was already on the target when I began to fire and select a weapon, it wouldn't shoot them :P (on selecting a weapon it should then immediately calculate the initial LOF to wherever the cursor is at that moment)
Now to do some runs in the heavier mechs I haven't tried out yet.