Plot: Knytt Underground is a 2D adventure game in the exploration subgenre similar to Metroidvania games, with elements of arcade platformers, combining the mechanics of the developer's previous games, Knytt and Within a Deep Forest. Wikipedia
Plot: Eternal Daughter is a freeware 2D action-adventure game created by indie developers Derek Yu and Jon Perry and released on June 21, 2002, under the Blackeye Software label. Wikipedia
Plot: GridWars or GridWars 2 is a video game inspired by Bizarre Creations' Geometry Wars by Canadian developer Marco Incitti. The first version of the game was released as freeware on December 21, 2005 on Marco Incitti's Blitz Creations website. Wikipedia