Old mega man games for the Nes were godly, I can still remember Gutsman's stage in the first game, god that was hard. Even the mega man X games for the Snes were good, albeit allot less challenging.
The GBA Zero games were bleh though, the combat was nice but the fact that Zero looked so feminine and did that pelvis thrust thing all over the place was not too appealing.
I will admit, the battle network games were awesome.