The Edna & Harvey games are wonderful. Fantastic point & click adventures with fun visuals and dark & cheeky humor.
https://www.gog.com/game/edna_harvey_the_breakout_anniversary_edition
https://www.gog.com/game/edna_harvey_harveys_new_eyes
https://www.humblebundle.com/store/edna-and-harvey-the-breakout-anniversary-edition/
https://www.humblebundle.com/store/edna-harvey-harveys-new-eyes/
AER - Memories of Old is a beautiful, serene, non-violent adventure game. It has a interesting story evocative of myth and legend, and the flying is amazing.
https://www.epicgames.com/store/en-US/p/aer-memories-of-old
https://www.gog.com/game/aer
https://www.humblebundle.com/store/aer-memories-of-old
Wreckin' Ball Adventure is very fun. Physics platforming with rolling, swinging, momentum, and destruction. Multiplayer mode adds some fun chaos. Cheap right now!
https://store.steampowered.com/app/746030/Wreckin_Ball_Adventure/
Puddle Knights is a creative, charming, and very unique puzzle game. Help the nobles keep their feet clean. Tons of interesting puzzles with lots of clever mechanics. Also on sale for the Switch.
https://store.steampowered.com/app/1180540/Puddle_Knights/
Ghost Parade is a charming platformer action RPG based in Indonesian folklore. The visuals are magical, and you'll meet and recruit a variety of cute and spooky characters. A nice adventure with unique flavor.
https://store.playstation.com/en-us/product/UP1024-CUSA16151_00-GHOSTPARADE12345/
Naught is a challenging, twisty-turny, gravity-shifting platformer. Everything this game does has been done before, and yet it still feels very unique. An amazing game.
https://www.nintendo.com/store/products/naught-switch
Hidden Folks is just delightful. A huge, vibrant, monochrome world to explore, with tons of little details and lots of stuff to find. Like a Where's Waldo book come to life.
https://adriaan.itch.io/hidden-folks
https://store.steampowered.com/app/435400/Hidden_Folks/
Wife Quest is a goofy yet challenging retro action-platformer where a feisty young warrior goes on a quest to save her hapless husband from horde of amorous monster girls. Let jealousy fuel your fighting spirit!
https://www.epicgames.com/store/en-US/p/wife-quest-ed5224
Castle on the Coast is a charming and fun retro 3D platformer collectathon. Pretty easy and friendly, with optional co-op to make things easier, but really very fun. Perhaps unpolished compared to similar games, but wonderful. Also on sale for the Switch.
https://store.steampowered.com/app/1341900/Castle_on_the_Coast/
Red Ronin is a bloody, exciting, tactical, sliding puzzle, action game. Yes, it's something of a hodgepodge, which is both a strength and a weakness. Turn-based, except when it's not. Has some interesting twists.
https://store.steampowered.com/app/1222570/Red_Ronin/
Super Cable Boy is a weird and wonderful retro-inspired platformer. Great gameplay, strange visuals, secrets to discover. Challenging, especially the extra levels and objectives, yet friendly (nice accessibility options). Just fantastic.
https://store.steampowered.com/app/1304420/Super_Cable_Boy/
Pushy and Pully in Blockland is a cute and fun arcade co-op game that draws influence from several different retro classics but blends them together into something wonderful and unique.
https://store.steampowered.com/app/1107820/Pushy_and_Pully_in_Blockland/
SPITLINGS is a wild, challenging, multiplayer arcade game. Somewhat inspired by Pang, but really unique, with limited ammo and lots of weird mechanics. Lots of levels and unlockables and more. Crazy fun.
https://store.steampowered.com/app/1002000/SPITLINGS/
Jack Axe is a cute and fun, yet very challenging platformer set in a world that is a charming fusion of Norse and Filipino mythology. This game is delightful. And it has co-op!
https://store.steampowered.com/app/985780/Jack_Axe/
Hoplegs is amazing, I mean, it's already a creative and interesting idea, but it's executed with so much charm and style... and I am TERRIBLE at it. DAMN is it hard. Uh, yeah, looking for a platforming challenge? Yeah.
https://store.steampowered.com/app/1395830/Hoplegs/
Alekon is a colorful, charming photography game with lots to do. Minigames, special tools, quests, story. Clearly inspired by Pokemon Snap, but still incredibly unique and fanciful.
https://store.steampowered.com/app/1479390/Alekon/
I'm normally not that interested in westerns, but Luckslinger grabbed me from the start. Stylish and fun and very unique. And that music! Incredible.
https://www.nintendo.com/store/products/luckslinger-switch/
Fly Punch Boom! is a ridiculous, cartoony, over-the-top Dragon Ball-esque flying fighting game. The unique gameplay is straightforward but very technical. And FAST. There are tense moments of survival, showy defeats, and more. Also on sale for the Switch.
https://store.steampowered.com/app/1051960/Fly_Punch_Boom/
Wand Wars is a fun, chaotic, fantasy sports game. Like Lethal League, the ball you bat back and forth is also a weapon. But instead of jumping you're flying, and there are power-ups to shake things up.
https://store.steampowered.com/app/422110/Wand_Wars/
Flat Heroes is a challenging minimalist platformer about dodging a variety of threats. Seems simple at the start, gets hard and chaotic fast. Includes multiplayer modes, and extra challenges.
https://store.steampowered.com/app/508790/Flat_Heroes/
PHOGS! is incredibly bizarre and utterly delightful. Puzzles aren't that hard, but they are fun and interesting. Co-op must be crazy but I haven't been able to try it myself.
https://store.steampowered.com/app/850320/PHOGS/
Chariot is a cute and silly co-op platformer where you collect treasure by maneuvering a rolling coffin. Though playable solo, this game really shines when you play co-op, and it gets *tough*. Cheap right now.
https://store.steampowered.com/app/319450/Chariot/
Toodee and Topdee is a delightful mashup. Incredibly unique blend of a platformer and a sorta-Sokobanlike. More challenging than you might expect, thankfully there are lots of accessibility options.
https://store.steampowered.com/app/1303950/Toodee_and_Topdee/
Death Squared is a delightful and devilish co-op puzzle game for 2 or 4 players. Communication is key, and you'll have no hand-holding; this game expects you to wander blindly, die a lot, and learn along the way.
https://store.steampowered.com/app/471810/Death_Squared/
Never Alone (Kisima Ingitchuna) is an incredible platformer adventure of a girl and a friendly fox. It was made in collaboration with the Iñupiat people of Alaska, with a story based in their culture and legends. A masterpiece.
https://www.gog.com/en/game/never_alone_arctic_collection
https://store.steampowered.com/app/295790/Never_Alone_Kisima_Ingitchuna/
DERU - The Art of Cooperation is a great co-op puzzle game that demands planning, puzzle-solving, communication, and precision. Quite challenging. And it's pretty.
https://store.steampowered.com/app/632250/DERU__The_Art_of_Cooperation/
Batbarian is a fun, goofy, but still challenging action-adventure with a lot of cool ideas and mechanics. The writing is funny, the combat is great, and the puzzles are interesting.
https://www.humblebundle.com/store/batbarian-testament-of-the-primordials
Lost Words: Beyond the Page is a beautiful, thoughtful, wondrous platformer adventure. Has an emotional, authentic, dual layered story, and creative gameplay. Absolutely amazing.
https://www.humblebundle.com/store/lost-words-beyond-the-page/
https://www.nintendo.com/store/products/lost-words-beyond-the-page-switch/
Spinch is a challenging and visually stunning platformer. The graphics are wild and intense. Gameplay is mostly straightforward but very polished. Just incredible.
https://www.humblebundle.com/store/spinch
https://www.gog.com/game/spinch
The Sun and Moon is a tight, challenging, elegant platformer. Reverse gravity while playing in negative space. Paying close attention to your momentum is crucial. Cheap right now.
https://store.steampowered.com/app/321560/The_Sun_and_Moon/
Sword of the Necromancer is great. A challenging dark fantasy roguelite with some neat mechanics including recruiting dead enemies and very limited equipment, forcing you to make hard choices. Plus: Lesbians!
https://store.steampowered.com/app/1243890/Sword_of_the_Necromancer/
Pode is an absolutely enchanting co-op puzzle adventure. Everything is gorgeous in this cute game with interesting puzzles. Just amazing.
https://store.steampowered.com/app/944080/Pode/
Joggernauts is a crazy, chaotic, colorful, coordination, co-op runner. Hard, but with options to make it less so (or more!). Great fun for 1-4 players.
https://store.steampowered.com/app/747620/Joggernauts/
BOXNIGMA is a minimalist sliding block puzzle. Conventional, straightforward, and to-the-point. Lots of great puzzles.
https://store.steampowered.com/app/1818250/BOXNIGMA/
A Good Snowman Is Hard to Build, from Draknek and Benjamin Davis, is a friendly sokoban-like, that gets surprisingly challenging, but stays fun. You can hug the snowmen, it's adorable.
https://store.steampowered.com/app/316610/A_Good_Snowman_Is_Hard_To_Build/
The same team made Cosmic Express, a puzzle game that riffs on some familiar mechanics very well. It's very cute and very challenging.
https://store.steampowered.com/app/583270/Cosmic_Express/