Once you unlock the D6, Isaac will always start with it giving him a slightly different playstyle. Isaac is the most basic character with all his stats starting out reasonably decent and in the beginning there is little to no specific strategy involved when playing as him.
With all that explained let's get onto the characters themselves. From Afterbirth onward, you must get each mark checked off with its hard mode version to unlock all secrets for the corresponding achievements. To add the red version, you must clear that boss/bonus area on Hard (Greedier mode for the bottom-center mark). Delirium (Causes the post-it note to become crinkled/bloodied around the edges)ĭefeating each of the above will put the corresponding image on that characters post-it note.Greed Mode (Greedier Mode for red mark in Afterbirth+).From top to bottom, left to right the symbols represent which bosses/bonus areas the character has defeated which are.