Yume Nikki
Yume Nikki the game that inspired Undertale and Omori, this 2004 Japanese 2d game made in rpg maker is a very surreal experience to be had. You play as this girl who goes to bed to wake up in a dream world, outside her room are different world to be explored and find effects that you can use to get other items such the umbrella to remove fire or to receive the game ending which will not spoiled. This game is free to play on steam and it's old so anything can play it. Do it, if you're not easily unsettled. Yume Nikki is basically like taking acid but as a visual walkthrough. This game isn't about gameplay, but about an experience and adventure. With it's limited capabilities, it really does set the world of Yume Nikki and I found the game super surreal and scary somehow, Yume Nikki does a perfect job at putting you uneased at all times, even though nothing really happens; the music soundtrack (which is now one of my favourites of all time) and visual really fit perfectly