The Binding of Isaac: Rebirth

I hope they have some really cool filters that you can unlock. It seems wasted if the only thing they add is a smoothing filter. Kind of like Serious Sam's blood filters. Hippie forever best blood filter (it turns all blood into flowers and all body chunks into stuffed bears, carrots, and other stuff like that, it's hilarious).

Yep, unlockable filters are a thing:

the flash filter is just one of a few filters that were added to the game. here is another.
these other filters are accessed by using “secret seed codes”, rebirth will feature 50+ secret codes that can be found within the game. these codes will change how the game plays/looks/sounds/etc. mostly for fun but a few of the codes we especially added as little challenges and/or to be played in speed runs or the like.