I wrote this using love, so it should run anywhere love runs (Windows,
Mac OS X, and Linux).

The controls are,
* right - go right
* left - go left
* space - jump
* r - reload
* l - build a random level (cavern)

It is obviously very much unfinished and currently just a toy. Oh
well, maybe next time.

Edit: I added Windows and Mac OS X ports. Windows now has double-clickable "cavern.exe", and Mac OS X comes bundled with love, so you can drag "cavern.love" onto "love.app".

Edit 2: Sorry, I forgot to change the links from '.zip' to '.tgz'. Serves me right for not trying them.