Rhythmic dungeon crawler Crypt of the Necrodancer [official site] was one of my games of the year back in 2015. It would probably have made the list for the shopkeeper's song alone but the game itself is ace, beat-based combat. Anyhoodle, the base game now has DLC prequel, Amplified, available in early access as the devs fine tune the experience.
Included in the DLC is a new protagonist, Nocturna, who you can hear a bit from in the trailer. Her deal is that she can switch between human and bat form. There's also a new zone, new enemies, the addition of familiars who help you fight, a new boss battle, more than 20 new tracks and some other bits and pieces.
Not everything is in place yet because Early Access. That means some more gameplay modes, items, playable characters and the like will trickle in.
Brace Yourself Games explain the early access decision as follows:
"Crypt of the NecroDancer is a MUCH better game because of all the great feedback we received from our community during Early Access, and we know that the same will be true of Early Access for Crypt of the NecroDancer: Amplified. Also, Early Access permits us to get the DLC into your hands more quickly, and we know that there are many of you who are anxious to start playing!"
They add that "The full version will include the complete story mode for our new protagonist, Nocturna. (The Early Access version will not yet have all of her story cutscenes, nor her final boss.) The full version will also include at least 1 more playable character, new modes, new items, and more!"
They also clarify that the DLC's price will not change between early access and its full release (£4.99/$6.99 on Steam and a bit more on GOG) so there's no financial pressure to pick it up immediately which is nice.
The base game is actually on sale at the moment on Steam and GOG so you can pick that up for a few quid. Like I say, I absolutely love it so it sounds like a pretty good deal to me, even if you're not interested in the DLC.