If you could make any crossover game...

[Cecil_and_Kain]

Katamari Damacy and Tetris.

[Kilroy]

Katamari Damacy and Tetris.

YES I'M ABOUT TO GET MY FIFTH TETRIS IN A ROW

HOLY SHIT IT'S THE PRINCE

And he clears out 3 of my 4 rows.

That bastard ;-;

[SkyMyl]

Star Fox and Metroid. ^_^

[DSWiiMaster42]

How about a game where the Nintendo and Sega characters team up to save both their worlds from the evil villains? This gives me an idea for a fanfic...

It could have Mario with Sonic, Link with Max (from Shining Force), Kirby with NiGHTS (NiGHTS is a little like Kirby because he/she can turn into various things), Wario with Shadow, Bowser with Eggman, ??? with Beat (from Jet Grind Radio/Jet Set Radio Future), Agent J (from Elite Beat Agents) with Ulala (from Space Channel 5), etc.

[Tupin]

EarthBound and Paper Mario.

[Java]

How about a game where the Nintendo and Sega characters team up to save both their worlds from the evil villains? This gives me an idea for a fanfic...

It could have Mario with Sonic, Link with Max (from Shining Force), Kirby with NiGHTS (NiGHTS is a little like Kirby because he/she can turn into various things), Wario with Shadow, Bowser with Eggman, ??? with Beat (from Jet Grind Radio/Jet Set Radio Future), Agent J (from Elite Beat Agents) with Ulala (from Space Channel 5), etc.

Like the SubSpace Emissary...?

[Tupin]

How about a game where the Nintendo and Sega characters team up to save both their worlds from the evil villains? This gives me an idea for a fanfic...

It could have Mario with Sonic, Link with Max (from Shining Force), Kirby with NiGHTS (NiGHTS is a little like Kirby because he/she can turn into various things), Wario with Shadow, Bowser with Eggman, ??? with Beat (from Jet Grind Radio/Jet Set Radio Future), Agent J (from Elite Beat Agents) with Ulala (from Space Channel 5), etc.

Like the SubSpace Emissary...?

Except it would actually be good and not repetitive. 

[captainjacksparrow]

Star fox and Metroid. Fox gun shooting first person game

[Java]

Fox gun shooting first person game

I don't know why this made me lol.

[DededeCloneChris]

Star Fox and Metroid. ^_^

Hell yes! I'm with you!

[Triforceman22]

Mario, Sonic and Zelda Game.

Maybe even Metal Gear... ::)

[DSWiiMaster42]

How about a game where the Nintendo and Sega characters team up to save both their worlds from the evil villains? This gives me an idea for a fanfic...

It could have Mario with Sonic, Link with Max (from Shining Force), Kirby with NiGHTS (NiGHTS is a little like Kirby because he/she can turn into various things), Wario with Shadow, Bowser with Eggman, ??? with Beat (from Jet Grind Radio/Jet Set Radio Future), Agent J (from Elite Beat Agents) with Ulala (from Space Channel 5), etc.

Like the SubSpace Emissary...?

Good idea, although each character team should have their own type of gameplay.

[Lotos]

Pikmin and Donkey Kong/Kirby would be interesting to see.

[extraz]

every fighter game....with every fighter game

Doom and Halo

Mario and Sonic

Contra and Metal Slug

Duck Hunt and Doom

[SkyMyl]

every fighter game....with every fighter game

Doom and Halo

Mario and Sonic

Contra and Metal Slug

Duck Hunt and Doom

You already used Doom, and that combo made no sense.

I don't see how that crossover would be successful.