I don't know why Itchio won't let me reply directly to comments, so here's a short guide for anyone stuck trying to download it on Android: You need to install the first APK, open the app (and follow the game's instructions), then install the second APK, update it, reopen the game, and repeat the entire process.
In other words, you have to install one, open it, download the other, and reopen the game.
Without uninstalling either, you have to install one on top of the other.