Haha, sorry! You can see how many HP an enemy has by how many green crystals are on it. It's not the best system, but it's at least something. :)
Viewing post in Pink Spiders Take Multiple Hits Now? Evil
I think graphical details like this (and the "pink enemies are homing" thing) are really clever and cool but VERY difficult to figure out on your own, but once you learn them you'll never forget it. Maybe have the seed-friends in the camps give tips sometimes? Maybe further up the mountain they give better tips?