Really cool idea, and as Kasmilus said... that monster. Certainly gets you to pick up the pace!
I really like how methodical the whole thing feels. I did best by taking it slow, killing every enemy in advance. Like frantic mini games of golf.
I think it would have been cool to be able to warp to the sword while it's still moving, before it's landed. Bit more risk / reward as you're not sure where it'll be by the time you reach it. It could serve to speed the pace up. Also, might have been nice if you could pick up the shadow drops using the sword. Like maybe they'd stick to it and get dragged back when you recall the sword. Would be useful for any drops that wind up below you and would give the sword re-call another use. Or even the shadow drops then just stay in the sword, making it more powerful... So you have a choice between health and attack? I dunno, there's lots you could do with this...
But yeah, good stuff!