I recently wrote about this series in another comment on here and I wanted to expand on it. For those who don't know, Submachine is/was a series of 13-or-so flash point and click adventure games. Each game was based on "screens," and you clicked the edges of each screen to move around the game world. You could collect objects and then use them on other static objects in the environment to solve increasingly challenging puzzles. As of me writing this, there are 10 mainline games, Submachine 1: The Basement (2005) up to Submachine 10: The Exit (2015). Then there's the prequel, Submachine 0: Ancient Adventure, as well as a few spinoff games like FLF, 32 Chambers, and Universe, which is a sandbox game allowing you to explore all of the screens from every other game.
All the games are hand-drawn either on paper like the first few games or digitally like the rest of them by artist Mateusz Skutnik. His art style (trust me, google screenshots of the game) is really something I've never seen before, plus that added with the insanely creepy soundtrack present in all games has made his series into something I've really never experienced before. I've definitely played games with similar ambiences in either art or the music, but never the amazing combination I found playing his games. I remember loading up submachine 2 on my mother's laptop's awful speakers and hearing that droning soundtrack, mixed with the borderline creepy artstyle and feeling almost haunted by the games, but I couldn't stop playing because they were so mysterious.
In the games, avoiding any spoilers, the player character actually never sees another living person. Every other tiny interaction with other people is through things like computer screens or the notes they left behind. This also lends to a super creepy atmosphere as you play the game to discover these massive buildings without a soul inside them. You can find rusted video screens, chairs fallen over, doors left slightly ajar, doors left locked, but not a soul in sight. What makes it interesting too, is that despite being creepy there isn't a monster chasing you or your character going insane or anything like that. You're just in these empty, lived-in spaces with nothing but yourself and a bunch of puzzles.
I just wish I could experience a game like this again. Creepy, but not too creepy that I'm turned off from the experience, and cryptic but not too cryptic that it becomes confusing. The puzzles in the game can definitely be hard, especially from sub7 to sub10, but I always found myself drawn to solving them because I wanted to see what more Mateusz had to offer. Without going into too many spoilers, the story itself is also pretty damn deep for a flash game series.
Mateusz says he's currently working on Submachine Legacy, a version on steam that combines all of the games into one, and remasters both their visuals and their audio. The release date currently says "Q3 2023" so I'm really anxiously awaiting that, but I'm worried it won't be as interesting to play Legacy as it was to play the series through for the first time.
I remember trying to play those (and failing miserably because I of how young I was). Maybe I should give them another go.
You might want to give the "The Room" series a shot. It starts out as just a digital puzzle box, but gets more involved as the series goes on and explores lovecraftian themes. There are monsters, but they're set pieces or serve to further the story and typically only show up for a couple seconds or so in cutscenes. I personally dislike horror games, mostly because of jumpscares, and I'm completely fine with these games.
There are versions for iOS, Android, Windows, Switch and even a VR one, that is really well made. I would personally recommend the Steam versions, because they are a lot more detailed.
They're definitely easier as an adult, at least in my experience. The last 3 or 4 games in the series definitely require some pretty esoteric thinking, but the earlier games in the series are pretty easy as long as you pay close attention to things.