Here's a condensed version of the above charts, showing what the whole of Zebes looks like in terms of item dependencies:

Here's a condensed version of the above charts, showing what the whole of the BSL station looks like in terms of item dependencies:

Here's a condensed version of the above charts, showing what the whole of Zebes looks like in terms of item dependencies:

Here's a condensed version of the above charts, showing what the whole of SR388 looks like in terms of item dependencies:

Here's a condensed version of the above charts, showing what the whole of Zebes looks like in terms of item dependencies:

Notice all the one-way arrows.