I lost my first 2 tries because I didn't realize the pentagon was fuel and also I didn't realize you had to trade your supplies with the alien by dragging your items into the trade box. Maybe put a title "Trade" over that box?
Also, with the pentagon, you could add a spout to make it look like a gasoline container to get the idea across. I don't think you need a long tutorial, but something like an overlay that labels the main elements and basic instructions before stage 1 begins.