The Iron Iso is one of the Rebel Army's tanks featured in the Metal Slug series.
The Iron Iso is a heavy tank designed mainly for defense. It is heavily armored, serving well as an armed roadblock and as cover for troops and other vehicles like the Girida-O. Its 75mm cannon is powerful enough to demolish anything in its path. It fires its shells in an arc. Due to its high production cost, only limited numbers of the Iron Iso were produced.
Upgrades & Variants
Iron Iso: Most common version. Usually fires one shot.
Iron Iso MK II: Improved variant. It is seen in Metal Slug 1, and is better armored. Once damaged, it fires three-shot bursts
Mobile Iron Iso: In Metal Slug 3D, the Iron Iso are far more commonly found than in the previous games, and are capable of moving at relatively high speed.
Iron Iso II: Found in Metal Slug Attack, this Iso is painted blue and has a sandbag in front of it for additional protection.
Golden Iso: Found in Metal Slug Attack, this Iso is painted golden. It has the furthest range out of all of its variants.
The final look of Iron Iso appears to be inspired by German WWII tank designs:
Track and roller configuration, as well as hull shape, details and proportions resemble the VK 45.01 (P) very closely in-game (a scrapped prototype of the Tiger I - the turret was used, while the hull later was re-purposed for the Elefant). On the final concept art however, hull proportions and suspension resemble ones of Tiger I, while exhaust pipes make the rear resemble one of the Panther instead.
While the turret doesn't match the shape of the Porsche turret made for Tiger I (circular instead of rectangular) as well as the gun's calibre (88mm instead of 75mm commonly used on Panzer IVs instead), the gun mantlet and muzzle break are nearly identical. Additionally, details of the turret's side suggest that Porsche turret was indeed in mind.
Another thing that doesn't match the Porsche turret's design is the location of the top hatch (not centred), which likely was influenced by the look of turrets of the Panzer III, Panzer IV, and Panther. It all goes in line with the fact that German turret designs tended to have a slight forward slant (so that the gun could be pointed down - the barrel goes down while the breach inside the turret goes up).
The earlier, unused version of the Iron Iso's design is based on the German SdKfz173 Jagdpanther tank destroyer, or a StuG III Tank Destroyer.
The Mobile version of the Iron Iso recycles M-15A Bradley's chassis and adds a turret to it.