Thanks! The last boss is tough, but I think it's tough in a good way, and not in an annoying way because it's possible to dodge it consistently. Since it was the last boss, I wanted it to be a proper challenge, and I'm happy with how it turned out.
However, I think the main issue is that the previous bosses were too easy in comparison. I nerfed the second boss last minute because it was perhaps even harder than the last boss, and unlike the last one, the second was harder in an annoying way.
The difficulty jump is very big from the second one to the third one, so that's why it feels unfair.
Perhaps more bosses would make it possible to ease the difficulty curve, but that would be a lot of bosses for only 3 days project, so oh well.