Gentoo Rescue from Jagriff seems simple on the surface but it's a real brain melting puzzle game that's well worth your time. Disclosure: key provided by the developer.
I think I'm just too stupid for this one, but I enjoyed my attempt at it. When you look at it you might think it's just another block-pushing Sokoban-styled puzzle game. It's anything but that. Well, there's plenty of that sort of thing but it's also a whole lot more. The game is thoroughly deceptive and rewards your time greatly with a real feeling of triumph each time you beat one of the cleverly designed levels.
A "welcoming vibe" the developer told me, and sure enough it looks cute and inviting but gosh is it a tricky one.
The problem is that you're often moving multiple characters. Not at the same time, but each different type of creature has their own problem you need to solve. It's working out where each needs to be, and how to get them there, that's the problem. And it really did make me sweat and curse at the screen for what seems like it should be obvious, but repeatedly had me furiously scratching my head.
Gentoo Rescue takes place in an open world of nested puzzles, which is where metroidvania elements start to appear with meta-mechanics, recursion, and other surprising twists. The developer compared it to the likes of Baba Is You, Patrick's Parabox and Stephen's Sausage Roll and that's not a bad way to look at it. Simple design, but unless you're some kind of genius you'll probably get stuck a few times.
There were times I simply had absolutely no idea what I was doing, which is not to say the design is overly confusing, it's just I had to walk away and come back with a fresh mind to solve it. The solution was right in front of me, I just couldn't see it. Maddening.
Thankfully, there is a hints system which can give you hints for each level across multiple points. So you could grab just one hint to get you on your way, or grab more to really explain things. It's a nice middle-ground for people who get stuck but don't want the full solution right away. Still didn't help me half the time. The way the creatures wobble when selected, it's almost like they're mocking me.

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Game Highlights:
- Penguins, walruses, and fish! Each introduces opposing win criteria.
- Rapidly expanding set of mechanics and interactions.
- Over 300 diverse, hand-crafted levels. No filler!
- An interconnected network of puzzles with item-based progression and metagame twists.
- Journal for tracking mechanics, which also lists entries needed for the current puzzle.
- A tiered hint system that teaches a deduction-based approach.
- 16 biomes distinguishing areas and mechanics.
- Original music.
It has Native Linux support and a demo is also available.
A thorough challenge that you need to try. Really great design and the way it blends different puzzle mechanics together is quite amazing. An absolute gem.