I completed Metroid Prime 1 100% on hard mode without too much trouble. I died maybe once or twice. First playthrough on normal was hard though. Meta Ridley and Metroid Prime are bitches, and deep down in the Phazon Mines your primal survival instincts WILL kick in if you don't go well prepared.
I never played Metroid Prime 2 on hard, but I can tell it was difficult on normal. The boost ball boss can make you cry, and the underwater exploration in the swamp temple can be a pain because of certain enemies. Finally, Emperor Ing proved a worthy opponent. Dark Samus just required a trick.
I also never played Metroid Prime 3 on hard, but that game had plenty of nasty bosses on normal. The final boss can kill you by simply bashing into you, and Valhalla and the Pirate Homeworld can be very challenging.
Reading this thread, I can't wait until the Metroid Prime Collection so I can do a guide-less 100% hard-run of all three games directly after each other!







