Pokemon Sun and Moon are the most refined Pokemon games ever made it terms of gameplay. Every generation adds more and more user-minded features that make the game more streamlined and less cumbersome, and this generation does that more than ever. For the first time they've really nailed the 3D environment (the 2D Pokemon games were perfect; they struggled with going to 3D for the first time in Pokemon X & Y). It feels more like a world designed in 3D from the start, rather than a 2D world that drawn with 3D art. They've also changed the Pokemon formula more than ever before. Gone are the Pokemon Gyms that we've all grown accustomed to, now replaced with a system of travelling from island to island to challenge trials and eventually each island's respective kahuna. The story is also a larger focus with each new generation; expect a number of cutscenes as well as scene jumps where you're skipped ahead in time to a slightly different location. Things are not just "character talks to you in a speech bubble for a while, and then you move on".
The downsides? That 3D world I mentioned can sometimes be a pain to navigate and learn. I found myself constantly forgetting where important locations were, and how to get back to them. This is because of a few things: for one, the camera will spin and pan around cinematic-style, which screws with your sense of direction; you may be running downwards (South) onscreen, and the road hooks to the left, but instead of turning your character, the camera turns, so you're still running downwards, except now you're running West. Over hours of playing you do start to get twisted around. On top of that there's the scene jumping I mentioned. A character may encounter you on a road, and says "follow me", so the screen fades to black and then you're in new location, and then they say "let's head back home", so it fades to black and now you're at that character's house. It hinders your ability to form a proper "mental map" of the world, learning how each place connects to the next, which makes navigation very frustrating sometimes, The map is awful; they put in on the bottom screen, and when you click on the center, it just talks to you. You have to click off-center to open. I couldn't figure out how to open the map for hours. Actually, you don't even get the map for quite a while as it is.
All the multiplayer features are in one part of the menu in a strange 2nd world kind of environment, with a sort of mini-game aspect to it. It's called Festival Plaza. They've done this type of thing over many generations, and it always turns out being very weird and disconnected from the rest of the game, so much so that I usually don't use these features. I think it's the developers' way of taking years worth of various multiplayer features, added game-by-game, and trying to collect them all into one cohesive menu. It's just not gonna work.
And finally, the actual gameplay itself. Like I said it deviates from the norm more than ever, but it also feels less like Pokemon with each passing generation, and more like any other generic JRPG. Also, there's not many new Pokemon; over the first 12 HOURS of play I had only caught 2 of the new generation Pokemon. Most of the others were Gen 1. Perhaps that is because of the popularity of Pokemon Go, they know a bunch of people are gonna be returning to the games, so they crammed the beginning with Gen 1 Pokemon. Maybe not. Either way it's pretty disappointing.
Overall the game is fun, but I honestly think the problems I mentioned all combine to to make the new Pokemon games feel just a little less like Pokemon than they should. They're missing a lot of the charm of the older games. Pretty much the only thing that's still around from those days is catch Pokemon and battle them. All the other aspects of the game, the atmosphere, the FEEL of Pokemon gen 1-3 is gone, and these new games are left feeling a bit empty, generic, and kind of part their prime. Please know, this is coming from someone who has played every single mainline Pokemon game; and yes, I mean every single game, each version, not just 1 version from each generation. I don't like having to say it, but it's what I feel; Pokemon is getting more and more refined while also becoming less and less of what many of us consider to be "Pokemon". I think that new players will enjoy Sun and Moon quite a lot for what it is, but players with experience in older Pokemon games will likely notice the significant change, and may find that it doesn't quite measure up to what they're looking for. I am sticking with a 4-star rating, as I do recommend the game, but with the understanding of the qualifiers that I've mentioned here.