As a longtime LOTR fan, I couldn't wait to get my hands on Middle-earth: Shadow of Mordor and, after 35 hours of playing it to reach 100%, I can happily say that it did not disappoint. Graphically, it was very impressive--granted the only other PS4 game I've played is Thief so I don't have a lot to compare it to, but the graphics were by far superior to any past-gen games I've played. The scenery did get somewhat monotonous since you only explored Mordor instead of getting to visit a variety of locations as in past LOTR games, but the game did a good job of showing that Mordor is not just the barren wasteland we see in the movies.
The combat was very smooth and, as someone who has played both the Batman Arkham games and the Assassin's Creed games, it was very familiar and so quite easy to get the hang of. I also noticed some definite improvements in combat in comparison to the Batman and AC games, namely with countering your enemies' attacks--in the Batman and AC games I often had trouble timing my counters and the game didn't seem to always register when I hit the counter button, but I had no problems with that in Shadow of Mordor. Also, I was very glad to see that although much of the controls and gameplay are taken from the Batman and AC games, Shadow of Mordor reduces the element of stealth quite of bit, which was a relief since I really suck at stealth. There were very few missions that required you to remain undetected (and most of these were side missions) and, unlike the Batman and AC games, when you did get detected and swarmed by enemies, you actually have a fighting chance because Talion has very respectable stats that make him a formidable fighter so you are not dependent on remaining unseen to survive.
Speaking of Talion's skills as a warrior, the game features a nice selection of upgrades for Talion that range from teaching him new moves to adding HP and the number of arrows he can hold at a time. You can also unlock five rune slots on each of his three weapons (sword, bow, dagger) and purchase runes to insert that give you special bonuses in combat--and, unlike in LOTR: War in the North, you can change runes at anytime instead of being stuck with what you chose, which is great since this means you can insert a lower level rune early on without worrying that doing so will prevent you from using a better rune you receive later on. Also, unlike a lot of games, it's actually quite possible to unlock all of the upgrades before you finish the game so you don't have to worry about which upgrades would be the most helpful as you will gain access to pretty much all of them before the final boss fight.
Another really neat feature in this game is the two sets of collectibles to find--ithildin and artifacts. Collecting all the pieces of ithildin allows you to view a cool image reminiscent of the one that appears on the doors of Moria along with a translation of what the runes in the image say. Collecting the artifacts, on the other hand, gives you access to extra information about Mordor, its citizens, and its history, which was a very nice touch and shows just how much effort the developers put into making this game really feel consistent with canon and making it as rich in detail as the books its based on--this effect is furthered by the inclusion of appendices entries for each of the characters, places, and creatures you encounter, all of which give the game a sense of great depth and realism.
In addition to these collectibles, there are also hunting challenges that require you to kill different creatures and survival challenges that require you to collect different herbs. These could get rather repetitive (particularly the survival challenges), but they are relatively quick to complete and offer extra experience and currency.
There are also four types of side quests (one for each of Talion's three weapons, plus outcast rescue quests that involve rescuing slaves from Orcs). The sword and bow quests did a good job of emphasizing a different skill for their respective weapon, but the dagger and outcast rescue quests could get rather repetitive.
The biggest feature of this game is of course the Nemesis system in which your enemies have distinct personalities and abilities and will remember running into you, causing them to seek revenge. Also as time passes, your enemies get stronger and even get promoted to higher positions. Ever since I first heard about this feature I was very intrigued by it and it was definitely an interesting twist to what I come to expect from video game enemy encounters, but I also feel that the focus on this system rather overshadowed other aspects of the game, particularly Talion's own story, which I was quite interested in and would have liked to have seen more of. However, I did like how the Nemesis system encouraged you to strategically think about the battles as each orc has different strengths and weaknesses that you need to be aware of if you want to have an easier time in battle. Also, I liked that the orcs weren't just nameless masses for a change but actually had names and titles and threatened and/or insulted you when you engaged them in battle.
My only real complaint is that there's no New Game+ and so there's not much reason to play the game a second time. After one playthrough, I feel like I've covered everything (except for a few trophies I didn't manage to earn) and while the side quests added some much-needed length to an otherwise rather short game, it still would've been nice to be able to play the game on a higher difficulty level as most of the battles were not super challenging once you got the hang of things. All in all, however, this game is awesome and a very solid addition to LOTR video game franchise and a very refreshing take on a series that has mostly stuck to the same storyline in each successive game, and I'm hoping that there will be future titles that explore previously unexplored facets of Middle-earth.