The Movie's pretty much exactly what you'd expect Wonder Woman movie set in WWI to be: Steve crashes his plane on themyscria, Wonder Woman Steals the sacred armor and weapons and stuff and goes to help him stop WWI, which she says Ares is behind. (Spoiler: she's kinda right)
The Good:
Nothing is especially stupid (except one thing I'll mention)
Costume design is good, EVEN ARES gets to wear his badass armour! (though his face isn't blacked out, but it's still there)
No one does anything blatantly out of their comic book character.
Action scenes are good, the last fight with Ares is really badass IMO.
The movie a does a decent job of showing how absolutely terrible WWI was, a war which, IMO is always overshadowed by WWII.
The Bad:
IMO there's just too much slow-motion in this film, like, yeah I get she can block bullets with her bracelets and that's cool and all but it wears on you after a while.
They kept the new 52 origin (though personally I don't take much issue with that)
They kind of portray Wonder Woman as kind of Trigger happy. (at least when she's a little kid, after that it's fine)
Spoiler: actual spoilers (click to see content)
Wonder Woman is apparently Zeus's ultimate weapon against Ares
According to this film, Ares kills every single god of Olympus, but loses to Wonder Woman in their first fight, seriously? The Literal God of War, who solo'd the entire Greek Pantheon loses to a Demi-god with almost no combat experience? (yes I know they state she was trained "10 times harder then every amazon" and is apparently "Zeus's ultimate weapon against him") So yes, the plot did justify it but I don't like it regardless.
I also don't like how all the Greek gods are dead, either.
Also, minor nitpick, but Wonder Woman has an Israeli Accent as an Adult, but Greek as both a kid and an Teenager, which is just kind of silly. (IIRC, could be wrong)
Spoiler: another, separate actual spoiler (click to see content)
So Steve is definitely confirmed dead, and we pretty much get to see al his interaction with Diana in this movie, but somehow Pine Signed a multi-Picture deal with Warner Bros.? WTF?