Saw this on indie game clinic and looked like my kind of thing so I tried it out and I love it!
Got three thoughts on how to improve things that bugged me:
#1, make the guy speed up once you've placed all blocks so you don't need to wait around for it to end when you can't do anything else.
#2 have a "best time" tracked for each level in addition to the 3 star rank. I'd keep playing levels after getting 3 stars if I thought I could get a better time but there's no way to keep track of that.
#3, show a preview line for the current pathfinding that updates as you place blocks (same thing as when you accidentally cut off the path but always on.) Figuring out the path isn't challenging, just tedious. You just need to wait and do nothing then retry. I feel showing it would clarify the gameplay and streamline decision-making.
And mobile is fun but releasing a paid PC build eventually would be nice too :)