well I did slay the boss but my final score is always 0 is that a bug cause I can definitely see the score going up as I slay those monsters .I also couldn't figure out the smash. but the dash and grapple were great!!
Sorry about the smash thing, you simply need to hold ctrl while falling from a high enough height.
(though due to some last-minute stuff you need a pretty massive height to activate it)
