In the Nintendo 3DS version there are two large soft platforms on opposite sides separated by a gap in the middle, a walk-off blast zone to the right on the right platform and to the left on the left platform, and multiple small soft platforms underneath the big soft platforms.
The Wii U version of the stage is similar in appearance to the Nintendo 3DS version; It has the two large soft platforms, the walk-off blast zones, and the many soft platforms underneath the large soft platforms. Contrary to the Nintendo 3DS version, in the Wii U version the large platforms are bigger and there are more small platforms underneath them, there is a piece of solid ground on both sides with a spring, and Metal Face appears when night comes. Metal Face can attack the characters with slashes and destroy some platforms with a laser shot. He can be KO'd. Similarly to the Yellow Devil, KO'ing Metal Face will cause an explosion damaging and knocking back all fighters except the one that KO'd him.
Image from Xenoblade Chronicles.
Wii U version.
Nintendo 3DS version.
Nintendo 3DS Stage Select image
Japanese Nintendo 3DS Stage Select screen
The Omega form of Gaur Plain.
Gaur Plain made its first appearance in Xenoblade Chronicles for the Wii. Gaur Plain is a location on the Bionis Leg. This stage can change from night to day reflecting a gameplay element from Xenoblade Chronicles. Metal Face is a Mechon that is seen throughout the journey in Xenoblade Chronicles. In the background, you can see parts of the Bionis Leg and in the distance the Mechonis, home of the Mechon.
This is one of the few stages that influence Final Smashes. Ike will never jump to the middle when using Great Aether on this stage, and Olimar will land on the left or right platform when using End of Day. This is due to there being a pit in the center, which would lead to a SD for Ike and Olimar.
Despite being called Gaur Plain, the location is not actually the real Gaur Plain. Gaur Plain can be seen in the background of the stage, while the fighting zone is actually on the landforms above Viliera Hill.
The landforms that are fought on are actually inaccessible in Xenoblade Chronicles, and are also much larger and further apart.
Despite Metal Face appearing on the stage as a boss he never makes an appearance on Gaur Plain in Xenoblade Chronicles.