Take a look around you and see how industrialized and complex our civilization and society are. It wasn't always this way. Humans used to not be able to do things that we consider basic. One of those things is communicating. Ancient humans had extremely rudimentary ways of communicating that limited them severely. As a way to adapt and overcome their environment, they had to develop their own language in order to communicate more effectively. Language is thousands of years old so, we don't know where every word ever comes from. However, as according to research by ancient historians and linguists, the word "mediocre" was invented by ancient humans as a response to playing this game.

Honestly, it's a pretty chill time. The movement is a bit of a step down from Pirate's Curse (so it's not quite as fun to speedrun), but it's still got the same charm and aesthetic as the rest of the series, and all the different abilities and transformations you get while exploring make it quite worthwhile. Only major complaint would be that some of the individual sublevels are a bit long, and falling off the stage or colliding with spikes forces you to start back at the beginning of the sublevel, which can be a bit of a timewaster. We have the technology Wayforward; checkpoints exist after all!

In summary, this game does nothing special but is still a solid game.
The levels are short and fun, they leave a lot of places out of reach so you come back to get the optional stuff when you get further into the game, an issue i have is that your transformations also have unlockable skills, so it's really annoying having the elephant but still not being able to break rocks below you.
The movement feels really limited when compared to pirate's curse, out of all the transformations only the monkey and the harpy (that you get at the end of the game) make for fast and fun ways to move, all the other might as well be colored keys for colored doors, you only use them for specific puzzles and most of them are just a check if you have it or not.
The game is very easy, you get a lot of health and healing items and you can even get all the shop upgrades after stage 2 if you do an easy exploit. Most of the bosses are beating by just hard tanking.
Regarding the dlc, i've played the risky one and friends to the end. Playing as risky is fun as you get most of pirate's curse moveset, sucks that there's no scimitar and the hat and cannon were nerfed behind skill upgrades, you get a bit less health but the strategy is still hard tanking, game is still very easy.
Friends to the end is terrible. Imagine playing the game with 3 health and slow and boring movement, supposedly this dlc is puzzle focused but that's only true for the (very fun and challenging) last level, the rest of the dlc is the base game, again, the dream squids are boring collectables that give you nothing. I stopped playing here because i really didn't want to play the same game again.
I've said a lot of bad things but i genuinely believe it's a fun game, just not the best and certainly worse than pirate's curse.

I think the majority of the Shantae games have progressively built to be better and better, Shantae: Half-Genie Hero seems to side step from Pirate's Curse formula ( A hybrid of Zelda/Metroid) and dived into being more purely Castlevania like (both Metroidvania and original versions). This honestly took me aback at first, and while the game certainly does warm up well enough, it just doesn't hit the exact highs that Shantae and The Pirate's Curse did.
The main problem with Half Genie Hero is just the lack of content it had going in. A lot of the base game plays as sort of individual levels and then when you backtrack to get more collectables the levels become a little more lackluster. Often the first time you enter new areas something big is going on, or an event is happening, but when you head back to get items or collectibles you missed or may need to progress, there is just half of what was there. It certainly isn't the biggest problem, but it certainly breaks the flow of the game. This is especially concerning with how well the Metroid format of interconnected worlds meant for collectibles, or how contained the dungeons were in the previous games.
While I think Half-Genie Hero still puts the correct steps forward in terms of platforming and the usage of Shantae's forms; the constant backtracking and nature of this game's story is off putting from the usual Shantae charm. Thankfully the game still has plenty to offer in terms of DLC and extra modes on top of the base game, and is easily one of the best looking Shantae games out there.