1. Hearthstone ; A late port to mobile, but my most played mobile game of the year. There's not a lot to say about this that I haven't said in my GotY list. It's a free to play card game with decent accessibility and depth. Not a great fan of its monetisation model, or its power creep issues, but it's still a ton of fun.
2. You Must Build a Boat ; Sequel to 10000000. Pretty much the same basic game, with more dialogue and upgrades. It's a good distraction.
3. Downwell ; The game I've played the least of this list, but it's a cute spin on the endless runner genre. Controls well, and is easy to pick up and play.
4. Contradiction - Spot The Liar! ; An FMV game with fun characters and interesting enough writing. Not the most accessible game on your mobile device if you mainly play outside of your home, but if you don't mind booting it up at home, you should find a worthwhile experience from it.
5. Her Story ; Another FMV game, but not a very traditional one. You're supposed to figure out what happened from a series of cut up clips of interrogation footage. You do this by listening to keywords of the clips you have, and using those keywords to search for new clips. Sort of shares its biggest issue with Contradition.
6. Neko Atsume ; My token Tamagotchi game of the year. It's dumb, but endearing and addictive.
7. Fallout Shelter ; I'm not really comfortable adding this, since I uninstalled it after two days. I have played it though, and little else, so it's going to end up on my list by default.
And that's all. I've also dabbled a bit in Best Fiends a bit earlier in the year when my niece installed it on my phone, but that's not a 2015 game. Curious to see what titles I've missed by everyone else's lists.