If you only saw this video - by Japanese voice actor and performer Sumire Uesaka - on YouTube, then boy are you missing out.
A rapid-fire tribute to the video games of yesteryear, the clip becomes something else when viewed as it was intended, on the record label's Tumblr. Click play there, and you'll be treated to something that should really be carrying an epilepsy warning.
Or maybe it already does, and I missed that bit when my eyes rolled back into my skull, bleeding.
Note: anime fans might recognise the tune: it's a cover of the ending theme to Hōzuki no Reitetsu.