Sustain My Existence is a representation of the state of mind of anyone who actually realises what money IS: random meaningless numbers. Physically, it's JUST ELECTRONS. THAT IS HOW DATA IS STORED IN COMPUTERS. Anyone who bothered to listen to Humans Incarnate would already know this. WE'VE FAILED. El hopelessly tries to make sense of humanity's only reason to keep lives sustained, that being dropping numbers, and he does his best to describe how fucking retarded a societal paradigm is when PEOPLE DIE FOR NUMBERS. It's a synopsis of the species, mixed with a cry for help, mixed with a statement of the limitations imposed on life: I need money so I can sustain my existence. Knowing all of this makes El feel fucking useless and hate himself, but are you any better?!
El was going for something that was halfway between 'vaguely grunge' and 'vaguely metal' with this and the other few songs that Falsified Necessity starts with. The idea is that the sound gets heavier and hits harder as the album goes on, though he's obviously ignoring quiet parts in later songs with that statement. When El initially set out the setlist he wanted for the album, there were more songs leaning towards 'vaguely grunge' than what there ended up being.
The link on this page will take you to the album mix.