What a neat little game! It feels like some of those old PDA games that were really good but nobody remembers because of the platform they were on. It seems like there might be a cap on how high some of the characters can go. I cold see this, or some version of this being expanded and grown into a full puzzle game. Good work!
Yeah some of the characters are blatantly better or worse than others. It's unavoidable since the game is so simple. I can guarantee that all of the characters can win (spoilers, you can win) though! Some will be harder than others though.