These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Awesome Music: Two particularly memorable singles from the movie, "Hold Me Thrill Me Kiss Me Kill Me" by U2 and "Kiss From A Rose" by Seal (which won him four Grammys, including Song of the Year). Elliot Goldenthal's score was not too shabby either, but your mileage may vary as to whether or not it was up to snuff with Danny Elfman's music.
The soundtrack is top-notch, including covers of "The Passenger" and "The Hunter Gets Captured By The Game", "Smash It Up", "8", and one that's totally appropriate for The Riddler: "Bad Days".
Contested Sequel: It's considered either fun despite being inferior and Lighter and Softer, or just outright disgraceful. On the other hand some people prefer it over its predecessor for giving Batman more screentime, and treating him more heroic rather than the borderline sociopath.
Val Kilmer as Batman is considered either a travesty of casting, or the first and so far only time an actor has really gotten and portrayed the modern version of the character (he's Batman all the time, whether in or out of the suit, and Bruce Wayne is the costume he wears). To Kilmer's credit, however, Bob Kane stated that he was his favorite actor to play Batman.
Franchise Original Sin: The movie adds a lot more humor, big-scale action sequences, memorable architecture along with a more form-fitting Batsuit that looked (and was, for the actor) more mobile. These elements worked in its favor for being somewhat truer to the comics, but retrospectively Batman and Robin was criticized for all those things (campy humor, gratuitously grandiose action, outright Bizarrchitecture and the nipples on the batsuit) such that it was distracting rather than immersive.
Fridge Horror: Sure Batman wins in the end, but there's still a handful of thugs out there who may or may not know that he's really Bruce Wayne behind the mask.
Ham and Cheese: Downside; the first movie in the franchise to have Bat-Nipples™. Upside; Jim Carrey babbling about "brainwave manipulation", stating that his neon wardrobe keeps him "safe while jogging at night." Ham and cheese on rye.
Tommy Lee Jones, who seemed to have a rip-roaring good time playing Two-Face.
Harsher in Hindsight: The movie, while not up to the Burton/Keaton standard, was really not that bad on its own merits, and Jim Carrey's Riddler was actually quite well received. Unfortunately Batman & Robin was so bad it actually made this movie look worse by association.
Hilarious in Hindsight: The rejected "Captain Kill" wardrobe design from Nygma's blueprints is a dead-ringer for Colonel Stars and Stripes, Carrey's character in Kick-Ass 2. (This works on multiple levels, as Carrey disowned both.)
Dick Grayson claiming he's Batman. Or mayber a reverse version since he was handed the mantle briefly in 1994 for the Progidal storyline.
Both Two-Face and The Dark Knight's Joker commandeer a semi in the same fashion.
Two-Face: *shoves driver out of the way* We'll drive, thank you!
Joker: *pushes lifeless mook out of the way* Excuse me! I wanna drive!
Even better, Two-Face's Motive Rant in the beginning, about why the flip of a coin is the only kind of justice, is similar to what the Joker would feed Harvey in The Dark Knight.
Ho Yay: Two Face and the Riddler are getting pretty affectionate towards the end of the film. They were cuddling.
The Riddler's last outfit change is inspired in Two Face's half suit half Elton John outfit. And he acts like a fanboy when he sees Two Face on Tv for the first time. Two Face is what inspires him to become a villain, and the first person he goes to see after his dramatic change. Fanboy much?
Foe Yay: The screenwriters and Jim Carrey describe Nygma's obsession with Bruce as "love" and "like a stalker".
In Name Only: Debatable. Some fans think Two-Face in this movie is more or less the Joker in personality, with Tommy Lee Jones even giving a performance similar to Jack Nicholson's. There is an internet joke that Two-Face is Nicholson Joker #2 and Riddler is Nicholson Joker #3.
Strangely, there were times Jones seemed to channel Cesar Romero instead...
Magnum Opus Dissonance: Most people don't have very strong views on Val Kilmer as Batman with the kindest opinion being that he was good but had bad material to work with. Despite this, Bob Kane (Batman's creator) thought he played the role best.
Moral Event Horizon: The film has an In-Universe example. Fred Stickley decides Edward Nygma went over by using him as a guinea pig for his brain manipulation device thing. Despite being an overall awesome and funny villain, Nygma really went over later in the same scene by pushing Stickley out the window for firing him and trying to report him to the proper authorities. He cements it when he tampers with the security log to make it look like a suicide, without caring one whistle about the repercussions it would have for Stickley's loved ones.
Narm Charm: This is a very silly film, but it's acted and directed well enough that you can't watch it without at least one cheesy grin.
The Problem with Licensed Games: The 16-bit games, published by Acclaim, is a platformer/fighter using Mortal Kombat-style controls. It was met with mediocre reviews. It also had huge loading times in the SNES/Super Famicom version. Easily one of the most frustrating of the games, in part because it combines the clunkiness of a Beat 'em Up with the blind jumps of a platformer(!), causing most players to become stumped on the very first screen. For this reason, The Angry Video Game Nerd gives this particular game a well-deserved ripping apart during his two-part Batman special. It might be worth taking the game for a spin, as it does experiment with some novel ideas.
There were also 8-bit versions (Game Boy, Game Gear) as well as a PC version that was similar to the SNES game with added CGI cutscenes. A 32X version was cancelled. A different game inspired by the same movie was released on the arcades, also by Acclaim. It was more similar to traditional sidescrolling brawlers like Final Fight. There were ports for PlayStation, Sega Saturn and PC. All these versions were panned by players and critics alike and Batman Forever as a video game became synonymous with The Problem with Licensed Games.
They Wasted a Perfectly Good Plot: The ingredients for a great story were all there: Batman questioning his identity and revisiting his origins. Batman discovering a child who has lost his parents much like him and trying to turn him away from the path of vengeance that consumed him. A villain smart enough to discover Batman's identity and destroy his lair. The inclusion of Two-Face, a very tragic and complex character. All of these plots combined should have made an excellent film. Sadly, too much focus was placed on camp and action and not enough on plot.
Took the Bad Film Seriously: Despite its uneven and sometimes downright goofy tone, both Val Kilmer and Chris O'Donnell give pretty sincere performances as Batman and Robin, respectively.
And Michael Gough as Alfred.
Vindicated by History: A very mild example. People still don't care much for the film and cite it as the moment the series went downhill but are at least willing to admit that it was nowhere near the catastrophe that Batman & Robin was.
Actually an inversion. It was received more favorably when it first came out. After Batman & Robin Forever got lumped with its successor and became known as the "downhill of the franchise"
What The Hell, Casting Agency?: The script clearly indicates that Dick Grayson is supposed to be pretty young (early to mid-teens, probably). They cast Chris O'Donnell, who was 25 at the time and looks it. This makes a lot of the scenes focusing on his character creepy, nonsensical, or both.
Especially since he's referred to as a "boy" on multiple occasions, and explicitly so in the novelization.
Oddly, there's a Lampshade hung on O'Donnell's age, when Bruce refers to "Dick Grayson, college student" as Dick's future "secret identity".
This all is essentially bad enough to create a gigantic Fridge LogicPlot Hole: Dick is obviously an adult, and no one really acts like he's not an adult (including allowing him to drive a car and/or motorcycle). So why does he get brought to Bruce Wayne's mansion and act like he has to wait for the authorities to leave before he tries to head off and catch the circus? He never should have had to leave it if he didn't want to, if he's a legal adult. Essentially, it's clear that someone involved was worried about the old child endangerment complaint regarding Batman having young sidekicks, cast an adult to alleviate them, but no one bothered to address the oddities this created in the plotline.
He was supposed to be playing a teenager. It's an obvious case of Dawson Casting.