I would like to share some of my ideas with you.
-if there is coming to be a client, then how should humblebundle users log in, because i got the game gifted so it doesnt appear in my game list.
In that case you should maybe add a serial system. Because at the end of every humblebundle link is a serial locate that you could maybe enter in the my game list.
-if you are planning multiplayer, it should be nice if you start with a lan function, so we can play it over hamachi.
-another "problem" i walked in to, was that if i downloaded a png file from the site, i didn't know how to open it in voxatron. Maybe you could add a local levels loader with a option in the menu? So we can store our png's and play our downloaded levels offline.
I love your game and i hope i can support you in your development this way :D
Thank you for creating another game i like!