Tobari 2: Dream Ocean

If you ever thought to yourself "I kinda like Kirby, but I wished it was actually challenging", this is it. It takes all the core ability absortion mechanics from Kirby along with some design philosophies from other stablished schools in platforming and delivers an uninterrupted string of very challenging and dynamic stages.
Character movement is a bit on the loose side, but it's still very reliable; stages can kick your butt but the game is pretty generous with lives and each stage has at least a couple checkpoints; there's some demanding platforming, but it rarely feels like bullshit and you always know that things are doable with a bit of focus or persistence.
It's all around a very well designed game, I feel like if it were released by a major company or a more well-known developer it might be considered one of the standout platformer games of the past few years. It's still at its core a hard doujin game, but its difficulty is a tool to deliver fun interesting stages instead of being hard just for the sake of it. Really good stuff.

The Tobari series is a blend of classic platforming tropes. Specifically, Tobari's spell-stealing mechanic is very similar to Kibry's, although she only gets one ability per spell she acquires, unlike more modern Kirby games. Beyond that, most of the level design philosophy comes from SNES Mario games. There are three collectable star fragments per stage, and many stages have hidden extra exits that lead to bonus stages. Finally, the bosses feel like a blend of Megaman and Touhou, of all things, with later bosses firing off downright bullet hell spreads of bullets.
Difficulty starts off extremely forgiving, even below the difficulty of New Super Mario Bros games world 1s, but by the end, especially in the bonus world you can only access by collecting all the star fragments, it gets up to Kaizo Mario/Mario Maker troll levels of difficulty.
Tobari 2 also has a clock and death counter with the final screen giving you your playtime, death count, and coins collected/spent for if you want to do challenge or speedruns. There are achievements specifically for doing things like 100% speedruns in less than three hours. (The game took me 20 hours to 100% the first time through, but there's a lot of trial-and-error, especially to find the collectable star fragments.) Likewise, try to beat the game dying less than 10 times or without spending any coins in the shops.
Tobari 2 is a fairly simple game, but it's a great entry to the genre and it's fairly inexpensive even when not on sale, so if you're a fan of classic platformers like the ones Tobari is clearly cribbing notes from, you'll definitely enjoy it.

Nice Mario-styled platformer with a copy mechanic similar to Kirby's.
Visually, the levels look quite underwhelming, but the gameplay and level design are very enjoyable. Difficulty feels right and it's rarely frustrating. Finding ways to collect every star in each level keeps even the easiest ones interesting, and it's fun to explore stages to find different endings, which lead to different stages in the map.
There is a much harder version of the game called Tobari 2: Nightmare. It's sold separately and it's only for kaizo enjoyers, so if you're into extremely hard and precise platformers, maybe try that version instead.

Mario meets Kirby meets Anime Girls in the obligatory beach episode.
The controls are a little tighter than the first game, and the difficulty is more even. It's not as kaizo as the average Desunoya game (until postgame), so you shouldn't worry about not being able to finish it.
Recommended for fans of 2D platformers.

I played the game in Japanese some time ago. A very well made platformer with lots of fun powers, interesting level design, and collectibles. Improves on the feel of the original, and the optional world isn't nearly as frustrating as the one from the original game.

Action side-scrolling and puzzle game much like Super Mario. Enemies will occasionally drop spells if you hit them with your staff, these come in a wide variety of effects, invariably they are essential in collecting all the optional stars in a level. If you aren't interested in the collectables, the game offers moderate difficulty, which can be lowered. The actual challenge in the game comes from obtaining all the collectables and the secret levels. So, if you are wanting a significant challenge in all aspects of the game, you may come off disappointed. The main boss battles and standard levels aren’t particularly difficult going for a straight run. If you enjoyed Tobari and the Night of the Curious Moon than this is your game.
In terms of improvements over its predecessor, it isn't a particularly different game. Offering some new spells and options, as well as noticeably more detailed, cleaner, and higher resolution graphics. If you enjoy sinking your teeth into a puzzle side-scroller for a lazy afternoon (or evening), there is a reasonable offer right here. The only real detraction is that the story is fluff, slightly better understood if you played the first, but ultimately forgettable. If you need a good story to drive you forward, this is not your game. Also, the mechanic whereby the only way to get spells is to hit the enemy with your staff can be annoying. Accidently stomp on an enemy or hit it with a stray spell and it’s time to restart the level (again though this is only applicable if you are collecting everything, so casually playing this isn’t a complaint).

I played the first game and loved it, and so far I'm loving the second game.
Nice platforming. The videos don't indicate how difficult it can be to get some of the stars. Completing a level is easy, but if you want to collect the 3 stars hidden in each level you have to be prepared to redo a section over and over until you land it right.
What is nice about this game is it lets you choose the difficulty and how much you get out of the game is up to you. It also has a nice setting, and the ability set can be interesting and with fun puzzles that also require reflexes.
Update: Having beaten the game I'll say that it's fun and chill until you beat the last boss. But once you find (all?) of the stars you unlock a hidden world where the dificulty quickly rises to hellish levels. Deep in the late game, it gradually became unfun for me as the death traps became more and more punishing, requiring incredible amounts of time to practice enough to finish short segments of an action puzzle.
And as if it's still not hard enough, the developer has created another version of the game called Nightmare Mode (which is as of this writing still unreleased on Steam,) where he drastically edited the stages to make them more them like Kaizo Mario than Kirby Super Star.
I wouldn't be very interested in that version as the kind of puzzles he used in the late game increasingly required practicing combos that needed fast reflexes, that became longer and longer, with more and more one hit death traps as you progress from the extra world to buying Nightmare Mode.
One feature this game barely utilized was the double magic. It's obvious from the extra world that the developer is a lot more interested in making puzzles than in creating combat scenarios where you'd use one ability over another, or have the freedom to choose between your favorite different abilities to clear enemies. The double magic is pretty wasted. It's so underutilized that it's practically a forgotten feature, and combat is somewhat neglected in the game.
You're way more likely to need to pick up two of the same magic to solve a puzzle in the extra world (i.e. two jump abilities) than to ever need two fire or to deal enough damage to clear a room of enemies. Abilities are more for clearing blocks than for defeating enemies.
Personally, I wish his games had more elements like in Kirby Super Star, with a lot more arena fights or levels with minor enemies with complicated movements and attack patterns that would require you to explore using different magic and combos in combat. Maybe some abilities could have even been stronger against certain enemies. But obviously, I'm not the designer, and the designer is more interested in creating puzzles and an occasional boss fight than in strengthening the hack and slash segments.