Inheritance
Planting a bomb on your ghost (either by touching them or some form of interaction), and detonating in the future to clear enemies / traps
Using your ghost to clear traps, but they dont die cos theyre a ghost
The more enemies you kill, the more powerful / aggro the enemies become
Map has several heavily defended areas / bases
Kill a boss / main enemy randomly placed in a base
If chara 1 kills 50 enemies, alert level 3 reached
Chara 2 needs to kill chara 1 to prevent them from killing more enemies and increasing the alert level
Hitmen VS Security (similar to UVSU)
Characters have 1 ability
Inheritance
Time limit for the first character
Level visual changes per faction
Characters auto run, if character 2 takes out the enemy that killed chara 1, chara 1 cont running forward