Nice puzzler!
Right now, spamming the weakest attack looks like the easiest strategy, though, because of how fast you can spam it, and how long it takes to charge the bigger one - you'd be able to attack + move + attack a few times while you wait to make the biggest charge (which you even can miss). Adding some recharge time after attack, or limiting the attack counts, or even just rewarding somehow for bigger attacks could make it worth it.
But overall - great submission! Also like the sound work :)