Ths standalone version of top-down run 'n' gun game Venusian Vengeance is now on Steam. Venusian Vengeance was serialized as 5 in-browser episodes here on Newgrounds a year back. The new Steam version contains the full game, as well as an all-new hard mode, which has faster enemies and tougher encounters.
You can get the game on Steam here: http://store.steampowered.com/app/351240/