Such a great game! You got a nice game all along. The only thing I would improve is really just the audio a bit, but it's not really necessary.
It's a great mini game, the only problem I can see is that you will need a lot of different characters to kill in order to make it a full game, or otherwise leave the kill part behind, but have character coming and going for some reasons. In this way on level X you might have to let 1 or 2 character go on a sub-quest, splitting the party and managing the two party with fewer choices. That would make a good option without having to kill the party, but still leaving the choice with consequences and ramification. Like, on level 2 you couldn't get the key that will be needed in level 5 that will give you one choice to get the reward Y in level 8. The game would be still playable, but the story will be heavily influenced.
Congratulations!