Released in May 2000. This game was the last game in the Metal Slug series developed by SNK. The underwater stages are a graphical nod to Irem's 1993 classic, "
In the Hunt". This is understandable as many of SNK's Metal Slug developers originally worked for Irem.
Metal Slug 3 features a number of sci-fi movie homages : Mission 2 features a guest appearance by the Men in Black. The carnivorus plant aliens in Mission 4 are a parody of the sci-fi musical comedy, 'The Little Shop of Horrors'. The squid-like aliens in the gigantic Mission 5 (known as 'Mars People') are a homage to the movie, 'Independence Day'. Also, the alien clones you face in this stage seem to parody the sci-fi movie clasic, 'Invasion of the body snatchers'. Finally, the last boss battle seems to be slightly inspired by the ending sequence in the sci-fi horror movie, 'Alien Resurrection'. One of the hostages (who also appeared in "Metal Slug 2" & "Metal Slug X", by the way) known as Hyakkutaro will join the fight by shooting fireballs.
Noise Factory released a limited-edition soundtrack album for this game (Metal Slug 3 Original Soundtrack - NF-0002) on 31/01/2003.
A hack of this game was released in 2005 as "
Metal Slug 6 [Hack]", one year before the official "
Metal Slug 6".