Season 1 of Glitchtale revolves around a failed Genocide Run, that transforms the timeline to a point where characters like Gaster and Chara have been revived fully. The season ends with Chara dying after they fought Asriel, who was resurrected, and with the Reset button destroyed by Frisk.
The first few episodes didn't have any voice acting, but with Continue, it adopted a Zelda-like dialogue method. The music of Season 1 were originally divided between many musicians, and eventually was concreted to NyxTheShield. Strelok also sounded the last episode, along with a compilation of all the episodes, which was made to incorporate his sound works in there.
Previous events have glitched the timeline enough for Chara to return as their own separate entity, allowing them to steal the essence of Frisk's determination; Sans and Flowey must team up to stop them.