I love that you have a README and License file (main criteria for open source category). Awesome README with inclusion of screenshots, and the content tags. I like that you have a blog post on this too. It's clear lots of work was put into this project. You even released it and have release notes; Kudos.
Very comprehensive game; start and load (very cool), and even has user preferences I can set. The game is really good; maybe start just a smidge easier so the first one or two battles don't take super long. The balance theme is subtle, yet effective. And I'm enjoying the sound effects and music. You've also done a really good job on the graphics. Kudos for an overall great game.