I think it's safe to say that I have an unhealthy addiction to just about all things Undertale, and I think the biggest thing fueling that addiction is covers of the amazing music from the game, RichaadEB and the work he does on his YouTube channel.
RichaadEB has made a series of metal covers of the big themes from Undertale, and they are earcandy.
If you've been looking to get down on some damn good metal covers of really good video game music, look no further than the Determination album that RichaadEB did with an artist called Ace Waters. Do yourself a favor and check out his YouTube channel. And if you like what you hear, go pick up his album on his Bandcamp page.