+ When a key is collected, it opens a lock.

+ Entities do not save if any entities complain.
+ key save prevention
+ throw error if keys and locks are't equal
+ lock save prevention
+ throw error if keys and locks aren't equal
+ throw error if not covering a filled tile

~ Hierachy needs to be changed.
~ WorldMap needs to be forwarded upon init
~ Player should be forwarded upon init
* Ugly as sin. Added to CONSIDERATIONS.

+ When a key is collected, it opens a lock.