First mashup attempt.

Clockwise from upper left:
Fortress story : Last battle http://www.youtube.com/watch?v=qLeIg4wmMaY
Last Battle http://www.youtube.com/watch?v=gQ5OWiLswxw
Brony Story - Last Mare http://www.youtube.com/watch?v=fcEgVXTumdY
My Little Cave Story Last Battle http://www.youtube.com/watch?v=bhhk44rTkM0