Skylanders: Giants builds upon the fundamentals of the first game, which merges a line of physical toy figures with a video game world.[10] The game introduced over 40 new toy figures, some of which are more than twice the size of the original Skylanders cast in both physical and virtual form.[11] The game involves connecting a physical toy to the video game console through a "Portal of Power"; whichever toy is used creates a respective character in the game.[11] Toy figures from the first game are also forward compatible with Giants,[11] although there are also new versions, called "Series 2", which have more powerful attributes than the originals. If the Series 2 Skylanders are used in the first game, they act as their own Series 1 counterparts. A new series of figurines called "LightCore" was also introduced, which glow when put on the Portal of Power and have a flash bomb attack in-game.[12] The game has a new and improved "Battle Mode" for head-to-head play, featuring more areas and gameplay options as well as offering a new variety of alter ego Skylanders.