These pictures say it all.
Megaman Nintendo System Games:
Mega Man – Famicom/NES, 1987
Mega Man 2 – Famicom/NES, 1988
Mega Man 3 – Famicom/NES, Arcade, 1990
Mega Man 4 – Famicom/NES, 1991
Mega Man 5 – Famicom/NES, 1992
Mega Man 6 (Japan/US only) – Famicom/NES, 1993
Mega Man 7 – Super Famicom/Super NES, 1995
Mega Man 8 – PlayStation & Sega Saturn, 1997
Rockman & Forte (Japan only) – Super Famicom, 1998 – Re-released as Mega Man & Bass worldwide on Game Boy Advance in 2002.
Mega Man & Bass – Game Boy Advance, 2002
Mega Man Anniversary Collection (North America only) – GameCube/PlayStation 2/Xbox, 2004 / GBA.
Mega Man X Collection (North America only)-GameCube / PlayStation 2, 2005/2006
Mega Man in Dr. Wily's Revenge – Game Boy, 1991
Mega Man II – Game Boy, 1991
Mega Man III – Game Boy, 1992
Mega Man IV – Game Boy, 1993
Mega Man V – Game Boy, 1994 (had additional Super Game Boy support)
Wily & Right no RockBoard: That's Paradise (Japan only) – Famicom, 1993
Mega Man's Soccer (Japan/US only) – Super NES, 1994
Mega Man X – Super Famicom/SNES, PC, 1993
Mega Man X2 – Super Famicom/SNES, 1994
Mega Man X3 – Super Famicom/SNES, 1995
Mega Man Xtreme – Game Boy Color, 2000
Mega Man Xtreme 2 – Game Boy Color, 2001
Mega Man X: Command Mission – GameCube, PlayStation 2, 2004
Mega Man X Collection (US only) – GameCube, PlayStation 2, Xbox, 2005
Mega Man Legends/Mega Man 64 – PlayStation, Nintendo 64, PC, PlayStation Portable (Japan only), 1997, 1998
Mega Man Battle Network – Game Boy Advance, 2001
Mega Man Network Transmission – GameCube, 2003
Mega Man Battle Network 2 – Game Boy Advance, 2001
'Mega Man Battle Network 3 White Version – Game Boy Advance, 2003
Mega Man Battle Network 3 Blue Version – Game Boy Advance, 2003
Mega Man Battle Chip Challenge – Game Boy Advance, 2003
Mega Man Battle Network 4 Red Sun – Game Boy Advance, 2004
Mega Man Battle Network 4 Blue Moon – Game Boy Advance, 2004
Rockman EXE 4.5 Real Operation (Japan only) – Game Boy Advance, 2004
Mega Man Battle Network 5: Team ProtoMan – Game Boy Advance, 2004
Mega Man Battle Network 5: Team Colonel – Game Boy Advance, 2004
Mega Man Battle Network 5: Double Team DS – Nintendo DS, 2005
Mega Man Battle Network 6: Cybeast Falzar – Game Boy Advance, 2006
Mega Man Battle Network 6: Cybeast Gregar – Game Boy Advance, 2006
Mega Man Zero – Game Boy Advance, 2002
Mega Man Zero 2 – Game Boy Advance, 2003
Mega Man Zero 3 – Game Boy Advance, 2004
Mega Man Zero 4 – Game Boy Advance, 2005
Mega Man ZX – Nintendo DS, 2006
Mega Man ZX Advent – Nintendo DS, 2007
Mega Man Star Force Pegasus – Nintendo DS, 2007
Mega Man Star Force Leo – Nintendo DS, 2007
Mega Man Star Force Dragon – Nintendo DS, 2007
Ryūsei no Rockman 2 Berserk x Shinobi – Nintendo DS, 2007
Ryūsei no Rockman 2 Berserk x Dinosaur – Nintendo DS, 2007
I WIN! YOU FAIL! GET OVER IT! YOU SUCK!