There's MOSTLY just those two endings, but a few weird easter eggs and variations depending on your gender, abra's gender, and the things you decide along the way
For one of the craziest easter eggs, if you make Abra upset at the end of the game -- she'll leave you alone for awhile. After solving a few puzzles by yourself (with no Pokemon) eventually Sandslash comes by. You can tell Sandslash something that makes Abra FURIOUS with you, and Abra reliates against you in a very weird way!!! I don't think very many people have done this, but if they do I bet it shook them a little...