The beginning of the Kirby Golden Age.

"The metroidvania one."
So what do we really have here? You start off as Mikey. You're trying to find and rescue your brothers scattered throughout a large continuous environment. Each turtle has a unique ability that allows you to progress deeper through the labyrinth.
You get a complete map at the beginning of the game with areas of interest marked with a nondescript dot. Unlike Castlevania, you don't see doors marked on the map.
The player is left to make educated guesses about where to press forward, and this is my favourite design element. The maze is fairly simple to actually explore but seems vast from the map. Navigating without a guide is not difficult.
What is difficult, is the bosses. They move too fast. They are too big. They have too many i-frames. As you learn their movements and improve your reaction time, they are beatable but it's not enjoyable.
The turtles themselves are fun to control. You have an air kick, and a generic attack. As best I can tell the hit boxes are the same for all turtles. You aren't able to spam attacks, they have about a half second cool down period, so you need to be precise with your strikes like with a Ninja Gaiden.
Music is good. Enemies lack variety. It's no Metroid II but it's interesting and competently put together.

I love this broke-ass game. That you can exploit the mechanics and one punch man your way through the most difficult battles is a strength, not a weakness. I love how each class has its own growth mechanics. I love all the bizarre effects your equipment can have.
Uematsu is in fine form, wringing out memorable melodies from the GB sound chip. The art design is strong. Everything reads really clearly and the enemies have fun, cute designs.
Overall it's a really impressive release for year one of the Game Boy. Mechanically I like this better than Final Fantasy I and II. Kawazu is a mad genius.

This is a snappy, fun little game. Great Hip Tanaka soundtrack. I really like the tension of letting go of your balloons or trying to make a quick pit stop to pump up a new one. The last level's cruel but that's what save states are for.

The ultimate expression of what the Game Boy was capable of, and probably the best Zelda narrative.

One of the absolute best games for the Game Boy. The depth of Kirby and his friends' movesets is incredible for the DMG. The Super Game Boy effects are really impressive, in how it's able to use careful palette swapping and positioning of assets to convey more colour than would otherwise be possible. You even get little extra PCM samples on the title screen. This is HAL showing off their mastery of the Game Boy as a platform.
(Finding Rainbow drops is BS, just use a guide)

I assume this is the shape of mainline Kirby going forward.

Bonk is a really interesting foil to Super Mario Bros. The game is slower, and more exploratory. You have a more acrobatic move set that Mario would really only adopt later. It's more forgiving in terms of letting you continue from where you've died, having health at all, and being able to expand it.

I really liked a compressed, more forgiving Contra experience. It doesn't overstay its welcome.
The animation of the palm trees are a great example of Konami polish.

This is right up there with Kirby's Dream Land for most impressive use of the DMG.

Nemesis on steroids. Multiple characters. Hard as nails. One of the best STG for the DMG.

I think this is maybe one of the strongest games for Game Boy Color as a platform. The set-back nature of failure is a bit frustrating, and I did save state my way through the golf mini games on an Analogue Pocket. A younger me would have brute forced it but time is precious.
The level design is excellent. There are always hints pulling you along without being overly overt. The mechanics feel very satisfying. Wario has a huge array of abilities and the game finds seemingly endless ways to exercise them.
Each treasure is gated behind a unique wrinkle to the gameplay formula. Environments are beautiful and varied. Bosses are whimsical and reasonably challenging. This one slipped under my radar when it was new even though I loved Wario Land II and this is such a welcome refinement of that formula.
This is absolutely a game that I'll go back and 100%.

This is about as much as I can probably enjoy a AAA game. Web slinging and controlling Miles feels great. Scenario design and mission structure hasn't changed at all since GTA III.

This is a really impressive homebrew, backporting some mechanics from New Super Mario Bros into Super Mario Land. Assets are sampled down or created from scratch where needed.
The jump feels closer to Land's than NSMB's, but the controls are tight and responsive.

Now they can finally put this approach to bed.