I don't play much actually. It's hard for me to find something that catches my attention.
And above all, I haven't finished most of the games. I almost immediately lose interest. If I had to choose I would say that Portal and Portal 2 are the best titles I have ever played (I finished these ).

As for video games with a psychedelic side...nothing comes to mind. I don't think you'll ever find anything really similar, also because the psychedelic experience isn't just visual.
Personally, however, I like to play something that creates its own atmosphere and immerses you. Among these I can name Journey, great game.

i have played portal 2 it was such a good game...i have great memories with that.at the end you watch a beautiful song.puzzles was amazing.there is lack of good video game i agree with you.
most games in these days are online and battle royal which i don't like it.
i played journey too.it came for PC last years or two years ago.(i don't remember exactly)
the graphics were really interesting but the story is very simple i didn't like the story.
if you liked journey.
do you know "PONY ISLAND"?i feel it's the most similar experience to bad trip with psychedelics.
it feels you are conquered by the devil and you are fighting to get back to reality.
there is another game of the creator of pony island called inscryption and it does feel the same but in other class and genre.
i suggest you play pony island it feels a little scary.

LSD: Dream Emulator is interesting

I had never heard it before, I have seen some videos and it looks interesting.
But I have to tell you the truth, I'm usually not very inclined to play horror or scary games. For example I can't play any Doom for more than 15 minutes. From that point of view I'm a bit of a coward

What is absurd is that for movies I have no problem, but for games I find it difficult to play them because I find myself really too scared. Maybe it's because with a film you have a third person attitude (or at least me) and you don't feel part of the context, while with games you are a first person actor.

Hi goodone22, I also have an interest in surrealistic and psychedelic games. I will definitely check it out, thanks for sharing your love for the game it sounds awesome
Have you tried a game called Thumper, it's dubbed as a rhythmic game, so great music and timed attacks, where you are a space beetle navigating a Railtrack defeating weird figureheads... literally.. very psychedelic visuals and light effects... also comes with a warning for photosensitivity so take care for those who are sensitive to those effects... interested to know what you think about it.. check it out...

i played the thumper after i read your comment here.thank you for your suggestion.
it was very hard and frustrating to me,it had psychedelic environment like fractals but it didn't feel like a drug.
there are some games which after i play them i feel i was high on a drug.