Did a lot with very little here, fantastic work.
I think the balance isn't very good, and your throw attack is too hard to hit, making the second phase of the first boss which ought to be faced with skill 2 very hard to do so, as you can't maneuver and throw your sword very well. I couldn't get past it, so I don't even know if it's the first boss or the only boss. If it's the only boss, that's making the most of the one enemy you have, if there's more I can't even imagine what can come after it, since this second phase is this hard.
It wasn't unfun or rage inducing though, it was fun and hard, which is good in my book. Big Blade Ben makes sense, as activating Big Blade is pretty much the default since it also lets you hit the small foes that recover your mana easily and safely, which lets you use big blade again. If Big Blade dealt more damage, it'd probably be enough to balance the second phase.