Woot! Yup, there are 3 other endings that you can get. To give a hint, there are 2 distinct choices in the game, and now it's a matter of how you choose for both.
I'm guessing you're thinking of the one that summoned a monster that shot fire or spikes or whatever? I believe the training hall midway in the game had something to do with that. If that's not the one you're thinking of, the only thing that comes to mind is maybe you're thinking a special attack in the final cutscene? Hard for me t o say, I'm afraid.
And, you are very welcome! Thank you so much for enjoying my game. You've no idea how much I appreciate it!