Hmmm, I think I needed a few tries for that one as well, and googling suggests it's not a very popular boss, at least pre-patch, but I also found it in the lower half of a couple of boss difficulty rankings.
I think ultimately, you'll need to find a way to trick its homing behaviour into missing you, I'm pretty sure it's possible to do that consistently, but I don't remember how I did it.
In other news, I just finished Hidden Folks (except DLC, which I'll probably play with my wife on the weekend) and it's fantastic. It's basically Where's Wally/Waldo - The Game. You've got these massive multiple screens spanning scenes and need to find a few specific people or items in them (you can get a short hint for each one and you see what they look like). Since it's a game you can also interact with some elements of the scene, adding some light point-and-click puzzle elements.
But most of all, the scenes, art and most of all sound effects are all really charming.
Took me 5 hours to beat, highly recommended if that sounds like something you might enjoy.
Just saw that the price for Shovel Knight is going to be raised to $40 with the release of King of Cards and Showdown. So if anyone was considering getting it at some point, it might be worth snatching it for $25 before then.