The core mechanics for this are the night essence - mechanically it acts as an Ultimate. Whether you’ve used it is kept track of with the variable N.
N0 (do not use Night Essence) - N1 (use Night Essence).
Finding all the memory fragments. These are found in special levels that players do not have to traverse. It is kept track of with the variable E.
E0 (no fragments found) - E1 (all fragments found).
Consuming the infected monster parts that players get from bosses. It is kept track of with the variable K.
K0 (No consuming the monster parts) - K1 (Consuming the monster parts.)