The trailer tells you that the game is about what a person thought when making a game. Without going into detail, I have personally become very interested in psychology after certain events in my life. And I am currently in a somewhat weird stage in my life, which made this game hit hard. If you are interested in why people do things. This game is very interesting. It's not very long, but during it's time it does everything it wants to do.
It's about expressing yourself through a medium, in some way. If you like intellegent movies and games, that makes you think and wonder about stuff, this is it.
For many games it would make sense to explain many things in detail, that's not really the case here. It should be experienced with as little preparation as possible.
This is possibly a rather bad review. But please be careful with reading more reviews, I fear many will tell much about the game, and tell too much. If you can not afford the game, or your computer cannot handle even source games, you can try a walkthrough of the game without commentary. Commantary would ruin it. Watch that afterwards or something instead if you want to.