Try fighting that Aurora Unit on Hard mode...  What a gaddamn pain.

Yes MP series is pretty hard but not ninja gaiden hard. also i may add i loved the MP series so i didnt care it was hard it was just awesome!!!... i would kill for MP4 on WiiHD looking like killzone 2.... OMG drool.......

1st MP i played was 3. Decided to play it on hard (whatever the max. diff. is on first playthrough) That Ice boss was HARDCORE and i died tons, infact i got stuck close to end of the game where you have to protect some soldiers while running along a path. Gave up on it and haven't played since but i will prob. buy the MP trilogy and maybe replay 3 on an easier difficulty next time.

Yes its hard and thats a good thing.

That Boost Guardian is beyond insane in the hard mode.

Yeah, Prime 1 was pretty hard, but Prime 2 was yankthecontrolleroutandthrowitacrosstheroomhard on Quadraxis(?) and the final two bosses. The main game wasn't a cake walk either. Prime 3 was just freaking easy after finishing Prime 2. I hope Team Ninja/Nintendo ramp up the difficulty for Other M.

Good lord yes.

I got back into MP3 again about a week ago (previously I had completed normal mode, and was 25% into Veteran) I had some trouble on Veteran with Helios... I died twice and had to start again... mostly because it had been so long since I played the game. I had a bit more trouble with the combination Dark Samus/AU313 at the end, died 3 times, but it was only on the verge of frustration.

However, I move onto Hyper Mode and started going through... it didn't really seem to change much, Rundas was a breeze.... Until Mogenar anway. I remember him being pretty easy on normal and veteran modes and I think it has to do with his recharge ability, in Hypermode difficulty it is much harder to take down the replacement orbs, so just to get a start on him I had to break 2 of his internal orbs before he recharged, that way I only had to destroy 1 of his replacements and it wouldn't be like going back to the beginning again. Then I could make a start on overloading the broken orb.
And while he is not very good at dealing damage to you normally, I find him hard to dodge when he puts those boots on, so after destroying his boots I often needed to  jump around a lot waiting for the green hand attack so I could get some life.

Because he was so difficult I had been dreading Helios on hyper difficulty as I had found it trickier than Mogenar on the easy modes.... so I prepared by finding as many extra life containers as I could with the current abilities, but then when it came to it I hardly lost any life in the battle, and took it down fairly quickly (like 7-8 minutes with 1 life, rather than what was probably almost an hour with 7-8 lives for Mogenar)

MP3 is pretty damn unforgiving on hypermode, gotta say im proud for finishing that one :D

havent played the other two but ill be sure to pick up the NPC trilogy!!

Yes, especially Echoes.

They are quite difficult but that goes back to the Ninendo and SNES days. The Metroid franchise has never been a Mario type of game that almost anybody can play and beat. Hell, you'll be dying several times on the last bosses for Metroid Zero Mission and Metroid Fusion as well. I have played and beat every Metroid game except MP3.... I'll be beating MP3 this holiday season when I finally pick up a Wii. And yes, Ive read on many reviews that they tweeked the difficulty down for MP3.

The Prime series definitely has some tough bosses. I don't really think the series is overly hard though. I think it is just right for the most part.

The exception to this is that boss in Prime 2 that you have to fight in Morph Ball mode. That part is complete BS.