I've had Nier Automata for a while and finally got around to sinking some real time into it over the past couple weekends.  I gave up when I first played the game three or four months ago, mostly because I couldn't figure out the combat on my own and got absolutely dumpstered in the tutorial mission.   The game has some odd camera angles that's done for the cinematic feel I imagine, but it made combat awkward in the opening segment of the game (and makes it a little clunky at times throughout the game, but it looks cool at least).  I had no clue WTF I was doing, not being able to see what was going on didn't help matters any either.

I cheated and watched a couple Youtube videos, nothing story related, just a how-to on the combat, and what I'm supposed to do for the opening/tutorial bit.

I've gotten all of the main endings I think, and a few of the joke endings inadvertently which are mostly just funny game over screens.  It's a very strange game, but a very satisfying one as well.  The music is fantastic (seriously - the scoring with poignant moments in the game is brilliant), the voice acting, especially at the game's climax is amazing, and the story itself...man, I don't know if I've ever cared about characters in a video game - both the good guys and the bad guys - like I do/did in Nier Automata.  Even the NPCs hit you in the feels with their dialog and stories.  

I don't want to spoil anything, but the development of someone other than the main protagonist I thought was especially neat.  A lot of games will focus on one hero or one character, usually the player-character, which makes sense, but in this game almost everyone has their story, and this character's story is very cool.  For me I'd say it is *the* story of the game, but it really is a beautiful story and needs to be heard and experienced first hand.

Nier Automata is on PC and PS4, I don't know how it runs on PC.  There's a few moments where it chugs piss pretty hard on PS4, but it wasn't anything that broke or crashed the game.  You'll probably want to play this with a controller, there's some combos/countering involved in combat that I don't know if they'd transfer well over to mouse/keyboard.  

So in short, this is a really, really good game.  A really strange game.  I never played the original Nier, nor any of the Drakengard games which I've read are in the same universe as Nier, and apparently there's a lot of Easter eggs in the game that go back to both of those games.  If you're looking for a good story, I think this is one of the better/best ones in 2017 to experience.

I got the first ending I was like "WTF...that's it?"

A whole new world opens up on subsequent completions.

Indeed.  For me at least, by the time I got to route C, I felt like I really knew and cared about the characters, and it makes the events of route C/D carry that much more weight.  The feels are for real.

I don't really think you're gonna miss that much without the DLC.  It's like three costumes and three arena events for $15.  I don't think there's anything except maybe some rare chip sets to be had that will really influence the main game.  I really like the game, but at this moment I don't plan on buying the DLC.