Positives:
+Added the Fairy type
+Mega Evolutions
+Some cool new pokémon like Sylveon, Tyrantrum, Greninja, Malamar, Pangoro, Dragalge, Zygarde, Diancie, Yveltal, Aurorus, Hawlucha, etc.
+Viola is a top-tier waifu.

Negatives:
-This game is brain-dead easy to the point of not being very enjoyable at all.
-The AI is so dumb it might also be called an "Artificial Stupidity"
-Most characters are bland and forgettable.
-Mega evolution was poorly implemented in the sense of some pokémon who received it were already strong to begin with (Garchomp, Tyranitar) or would've appreciated more a regular evolution instead (Banette, Sableye, Mawile).

Enjoyment: decent for the first 5 minutes then quickly got bored.

Terribly underrated Pokémon game. The Pokémon distribution is fantastic, the scenery is quite breathtaking for a 3DS game. As for the difficulty, there is none. But this is a child's game and franchise, if you want it you have to make it yourself. This game is a joy to nuzlocke and I totally recommend it if you've already tried it for the easier games and want something a little more challenging.

I must admit this is a game that has grown on me. The first time I played it I didn't think much of it "just another Pokémon game". But upon trying a few nuzlockes over the years I have come to adore this game. I can't rank it any more than a 3.5, as much as this is one of my favourite games in the series, as just as with many other Pokémon games, it requires too much input from the player to achieve it's full potential (You have to nuzlocke it, maybe even use external tools to randomize etc). However, this is an issue all Pokémon games have.