There are a lot of ways this game could be enhanced—why don't you try a few that are given:
The game currently lacks a pause option—why don't you add one?
Our game is naive with regard to multitasking. Once resumed, it will happily extrapolate where we should be in the cave after what might be a very long time. A better method would be to pause the game when it is backgrounded.
Try various control schemes until you find some you like, or change the existing schemes until you find something you prefer.
Use the gyroscope if available.
Add power-ups or other objects in the map that could affect the player for good or bad.
Make static levels for the game that could be loaded on demand.
Add logic to make sure any level is winnable.
Add sound and music to the game. You may want to investigate a plugin for low latency audio (http://plugreg.com/plugin/floatinghotpot/cordova-plugin-lowlatencyaudio).