In all honesty, I can't really find the words to write a review that does Love Is War justice- but I'm going to try. I've been following it weekly pretty much since I got into reading manga and it's one of the manga that made me really love the medium, so seeing it end is a bit of a surreal feeling to me.
This review should be spoiler free or close to it.

Having just ended, Love Is War has proven itself to be one of the best romcoms out there- and, honestly, one of the best manga, period. With great characters, genuinely funny jokes and gags, and a unique take on romance, it's more than worth the read.

In an era where overdone tropes and copy-paste romcoms are a dime a dozen, the idea of standing out by simply having the main pair not want to confess may seem like a low-hanging fruit. Akasaka has taken that idea and more than done it justice, flipping the basic idea of romance manga on its head. Using battles of wits and silly games to progress the romance, Love Is War manages something most romcoms don't- to stay consistently interesting even while the romance isn't in focus. There's enough romance to keep the plot going, but it's less of a main attraction than a fun side plot a lot of the time. A good chunk of the chapters are fairly standalone comedies, almost like a gag manga, but they still manage to build the characters and provide a constant stream of laughs.
For the overall story, Love Is War performs a juggling act between mini-arcs that drive the larger plot and standalone chapters, normally comedic ones, that flesh out the characters. It's fun and interesting, it has its twists and turns, and overall it's just extremely well done. It's not afraid to confront the flaws of its characters or to play around with typical romcom tropes- or subvert them. The sarcastic humor works extremely well with the characters, particularly Ishigami, and the gags are genuinely fun. When the series wants to be serious, it gets serious, and it does a great job using darker themes while still having those bitingly funny moments. It's a great story that can't be done justice in a few sentences, so I'll just say- read it. It's great.
As far as the ending goes, I thought it was decent. It's a typical case of "could have been a little bit longer", but I think it did a pretty good job overall and I enjoyed it.

As far as characters go, Love Is War does an absolutely stellar job of both creating great characters and developing them throughout the story. Getting to see Shirogane and Kaguya- who are already compelling characters at the beginning of the story- continue to grow and become more comfortable around one another and themselves is an absolute treat. It's a similar case with the notable members of the side cast, and even the minor characters feel like they establish themselves and their personalities extremely well, particularly Papa Shirogane.
Right off the bat, the characters are interesting. Shirogane and Kaguya work extremely well as foils, as do Ishigami and Miko. Chika works extremely well to let the rest of the cast act essentially as the straightmen in a straightman-and-funnyman sketch, and all of them have extremely well done, strong personalities that just make them interesting characters. You've got Shirogane and Kaguya, two somewhat arrogant, sarcastic geniuses, both of them believing they can trick the other into confessing ASAP. Chika, mostly oblivious to everything going on around her, just trying to enjoy the everyday. Ishigami, the antisocial, uncaring outcast, and Miko, the overly serious, uptight outcast in her own way- and those two developing as characters is honestly one of the best parts of the series.
While developing its characters, Love Is War is not afraid to showcase their worse sides, and that just adds another layer to their development. They can be petty, vindicative, arrogant, and downright assholes at times. When they mess up, sometimes hurting the people around them in the process, it's their fault, due to their flaws. They are not perfect characters or perfect people, and they aren't meant to be. They're flawed, and trying to present themselves, in many cases, as flawless- in short, they feel all too human. The nuance allows for incredible characterization and even more incredible character development, and the dynamics between the characters changing as they develop more is pretty damn close to the best character interaction in any story I've read- in both comics and novels.

The art is pretty good. Akasaka is extremely talented at drawing facial expressions, which makes some scenes way more impactful or funnier than they would be otherwise. It's not particularly unique or stylistic art, but it's the kind of good, clean art you'd expect from an experienced mangaka, and it suits the series extremely well. The paneling designs for stuff like inner monologues and arguments are awesome, and overall the art is simply well done.

Overall, Love Is War is more than definitely worth reading. The beautifully done characters and character development, hilarious sarcastic humor, and web of character relationships and emotion all combine into one manga- Love Is War, one of the best manga (and honestly one of the best stories) of all time.