1. Super Mario Maker
2. Majora's Mask 3D
3. Splatoon
4. Yoshi's Woolly World

Haven't played many new games this year, but so far it's Bloodborne for me. I want to try out Mario Maker and am almost certain it will be up there too

Mario Maker by far.

iirc, only played 2 2015 games but my vote goes to Splatoon

It's still a dead heat between Dying Light and Until Dawn. Two vastly different awesome games, both giving me dozens of hours of entertainment.
Third place will definitely go to Destiny The Taken King, they managed to improve everything that made me drop it last year, I cannot stop playing it and will probably occupy most of the rest of the year, along with NFL.

Nothing else deserves to be on my list, three games is plenty enough.

Ori and the Blind Forest; pretty much the only 2015 game I've played enough of the year to say I really liked it.

Bloodborne and MGS V!

1. Fire Emblem: Fates (all three; Birthright, Conquest and Invisible Kingdom)- Three Fire Emblem games at once, what more could you want? If they had gotten the Pokemon treatment and been the same game with a few different characters available, I'd have been annoyed; but all three play differently and feel like they could be standalone titles. Once you buy one, you get the others for $20 each (2000 yen, so I'm just guessing) so altogether they're excellent value too. Really, there's no reason not to buy this.

2. Yoshi's Woolly World

3. Super Mario Maker

4. Splatoon

Bloodborne and MGS V.

The Witcher 3, but Fallout 4 will probably be my GOTY.