Further and Rarer comes from a genre of games that purposefully has a lot of information and systems that are not explicitly explained in the game. These can be anything from secret locations, hidden mechanics, mysterious enemies, etc. The difficulty of the game drastically changes if you know more about the game. The game does little things to direct you to places to find these things out, but some will have to be figured out through trial and error. That is, unless you read spoilers: spoilers are things that tell you the secrets of the game without you having to figure them out yourself.
Why would someone not want spoilers?
The discovery of a game's secrets is a fun adventure and spoilers would take away from that experience. Not having spoilers also means the game has to be played a lot more carefully; the riskiness of the situation can be very exciting. Also, you can gain a lot satisfaction of being knowledgable about a game when you earned the knowledge the hard way.
Why would someone want spoilers?
If a game feels too hard or you feel like you have exhausted all the fun you can have from playing in a spoiler-free environment, spoilers may be a good experience. Also, some people really just want to get their stats to be big numbers and enjoy the process of getting as effectively as possible; spoilers really help with that.
How do I get spoilers?
If you the below button, it will take you to a webpage where you can read spoilers. I recommend you read all of this page to decide if you want to do that or not. They are called "spoilers" for a reason: once you read them, you will never get the experience of learning those things about the game organically.