If I could use one word to describe Happiness Charge it would be consistent. It's pretty much always a fun and entertaining show at the least, while there are parts that are better and worse than others its highs and lows aren't particularly extreme ever. I could always count on each episode to be basely enjoyable when I watched it even if I didn't expect much else.
The characters are fun enough. They have good chemistry with each other and I Hime in particular is great, she's definitely the stand out Cure from this season to me. Something of a problem though is that the show doesn't really balance out what it does with each girl. Yuuko feels like a prop for the first 30 episodes of the show and in the second half Hime is just kind of there. Not every Cure needs to have some sort of important side plot or be directly related to the main story in some way like Hime but there is really nothing going on for Yuuko and Hime at large stretches of time. Not only that but Yuuko's character is hardly expanded upon at all in the first half. Not counting Cures we have Seiji, Megumi's childhood friend. He's a pretty good character in his own right, and he becomes a nice support for the group of girls later on.
More than any other season Happiness Charge has a big focus on romance and love. It's pretty refreshing seeing this as a theme for Precure after so long. But it's not exactly done the best. A lot of it just ends up being characters agonizing over feelings and there not being good resolution on most things. Hime's potentially burgeoning crush on Seiji is wrapped up in the most disappointing and anti-climactic way possible, and in the worst case a possible love interest for Iona comes out of nowhere to enable a power-up and disappears just as quickly. For a show where love is such a big deal it really drops the ball in a lot of places.
In general the show is very quick to finish one thing and then move on to the next. Mostly in the second half. It will do something interesting and shocking for one episode and then it's done, time to do something else. The "Unlovely" event, which could've been expanded on so much more, and the resolution of Cure Tender are treated this way and it's a bit anti-climactic once again. The show does have a bit of a bad habit of bringing up supposedly important things and then just forgetting about them or seemingly thinking that they never need to bring them up again.
For a season where there are many different teams of Cures fighting around the world this wasn't really utilized much, they travel once and that's it. It's just kind of a shame they didn't really get to know that many other Cures well.
And then there's the CGI stock footage transformations. It's probably the most unique thing about HapCha compared to other Precure seasons. The girls each get some form changes and when they use them we get CGI stock footage exactly like the ending songs. They're very disappointing. The attacks themselves are basically pointless in the first place, very rarely do they even have an affect on anything other than the small monsters the Cures will be fighting. It basically just amounts to a weird cut-scene, "Oh. That happened.", and then they get phased out as the show goes on and we never see them again, it's basically just a waste of an idea. This only applies to the form changes used for battle though. The regular civilian changes are good, the girls get a wide variety of different outfits like ninja gear. It's one of the better realized parts of the show as they're always transforming into something cute.
The action in the show is overall the best we've had in Precure since Heartcatch. There's a lot of energy and excitement in the fights and the Cures are always inventing random attacks and throwing energy blasts and stuff that make the fights more fun. There's not really a ton of exceptionally well animated fights though but the show makes up for it I feel.
The animation isn't the best to be sure but the characters are very expressive and I feel the style and atmosphere of the show balance this out. I never found myself caring much about the general animation outside of fight scenes because Hime's exaggerated motions and such kept me entertained.
The villains are quite varied. The minion trio, like we've had every season since Fresh, is not particularly good. They have their fun scenes and are kind of basely entertaining but there's nothing else to them. They just kind of get worn out after a while. It doesn't feel like they have much of a rivalry with the Cures or anything and they aren't given backstories or any real development until much later than necessary. This makes the inevitable final fights with them just feel hollow.
Phantom is a better villain but still bland for most of his run. He later gets some development and what we learn about him makes him quite interesting but he's still not particularly compelling or fun to watch as a villain. Mirage is also pretty good and interesting herself but she just doesn't do much. The fight with her is indeed quite great though.
Deep Mirror is easily the best villain of the show. He also ends up as just being one of the most thought out, complex, and well realized villains of the franchise.
The finale is good definitely. Relatively well built up, intense, awesome, good villains to deal with, shocking reveals, it pretty much has all you could want. However. Megumi is the only Cure to be even remotely relevant to anything going on in the last part of the show. She does everything important basically. I don't know if I should be angrier at Doki for starting this terrible trend or HapCha for blindly following it. At least HapCha doesn't go out of its way to make things revolve around Megumi when they shouldn't though. She just... happens to be the only important one at the end. It's honestly kind of annoying.
The show uses a victim of the week format at a very loose level, we don't really get to know the people made into Terribads for the most part and they don't have to be sad or having a problem of their own like in other seasons. It's just a quick way to create a victim and a monster for the show and it's kind of nice truthfully, it at least means they never half ass the victim of the weeks story and they can still have important people made into monsters.
The normal non-cgi stock footage in the show is pretty good. All the transformations are good, Lovely and Princesse's duo attack is awesome, and the final group attack... well it's certainly unique I can tell you that much.
With all this being said the last thing about HapCha I can say is that there's just a feeling of staleness to it. Watching it I can't shake that it just all comes off as kind of bland to me. Probably having to do with Megumi's character, as fun as she can be, being really typical herself. But it's other things too that I can't quite describe, just a feeling the show gives off. But perhaps this is only because it's been ten years of Precure.
I would never rate Happiness Charge as one of the best or worst seasons of Precure. It's fine. That's it. It never evoked feelings of love or hate. But I could watch it and enjoy it again one day.