Complex sentence: An earlier video released on February 14,2011 promoted the cooperative aspect of "Portal 2" as a St.Valentine's gift and "lit up our preorders, our buzz, all the metrics that are used and collected by publishers and retailers".
Split into simpler sentences: An earlier video release on February 14,2011, promoted the co-operative aspect of "Portal 2" as an ideal Valentine's gift. The video "lit up our preorders, our buzz, all the metrics that are used and collected by publishers and retailers".