How to download original game, link? Also pls put on steam and add gamepad support
If by "original game" you mean the version made in 48 hours for Ludum Dare, just download "serum_run_COMPO.exe" from the downloads page. Sorry, I guess the meaning of "compo" is not clear for people not familiar with Ludum Dare.
Publishing on Steam would cost me $100, and so far I have made precisely zero dollars from this game, so there is no plan to publish on steam at this point.