How to find tips about The Forgotten

Solution 1:

The Forgotten is a secret character in BoI:Afterbirth+, only made available with the most recent "booster pack". As with several other secret characters in past expansions, there are almost no signs of his existence in-game. In fact, the only sign that there's something hidden at all is if manage to beat the first floor boss in under a minute, which will cause Mom to call out Isaac's name. Once you've done this, you need to explore (as Edmund mentioned in his tweet) the first floor very carefully and make note of any differences. Other than that, a typical player who doesn't already know about the Forgotten would probably never find out about it.