The shotgun in deadly action.
The "M90 Shotgun" is one of the guns featured in Mushroom Kingdom Fusion. It first appears in World 9-7, The Library.
The M90 Shotgun packs a powerful punch. However, it is short-ranged and has a slow rate of fire. It's power level is 125.
| Metal Slug-based: | Heavy Machine Gun | Fire Shot | Iron Lizard | Rocket Launcher |
| Contra-based: | Machine Gun | Rifle | Spread Gun | Laser Gun | Crush Gun |
| DOOM-based: | DOOM Rocket Launcher | DOOM Shotgun |
| Quake-based: | Grenade Launcher | Lightning Gun | Nailgun | Railgun |
| Halo-based: | Covenant Plasma Pistol | Covenant Plasma Rifle | MA5B Assault Rifle | M90 Shotgun |
| X-COM-based: | Plasma Rifle | Sonic-Blasta Rifle | Gauss Pistol | Sonic Cannon |
| Other: | Fire Rod | Ice Rod | Auto-Snifit | Metool | Lancer Assault Rifle | Shock Roach | NES Zapper | Plasma Discharge Unit | Raygun | Remington Shotgun | Thompson "Tommy" Gun | Karabiner | Luger | Mega Buster |