When you first encounter Eddie, he's a fat manchild puking in response to extreme distress, in a state of severe indignity: His ass crack is hanging out, and he can't seem to
stop puking. As with meeting Angela, James' interactions and
reactions (or lack thereof) help to further establish
his character - In fact, every character in Silent Hill 2 serves as a mirror to reflect particular aspects of James' personality: He expresses lack of genuine empathy, flat affect, lack of self-consciousness over social awkwardness, impatience, the half-heartedness with which he offers what he thinks are appropriate platitudes of comfort, etc. These moments all exist so that the moments in which James overtly reacts with denial, indignation, or panic jump out enough to indicate story progression.
Given what weirdos James and Angela are depicted as being in their (relatively) mundane interactions, Eddie's portrayal within the extreme circumstance of having ostensibly just happened upon a violently murdered man shoved into an apartment refrigerator in a way difficult to make sense of persuades the audience to see him as relatively innocent and naive amongst the cast introduced so far.
Because of the graphical limitations of the game's FMVs (Remember: if Remake GUD cause graphics GUD; then Original NOT GUD cause graphics NOT GUD), much of Eddie's acting is done with his eyes. Even though the model is largely static, the perspective forced by the camera angles and his body language (such as averting eye contact, and other sheepish behavior which only subsides when he's depicted comfort-eating) allow his character the range to transform over the course of the game through little more than clever cinematography. His expression goes from a dullard understandably disturbed by this extreme environment:
To a state indicating disturbance instead originating from mental illness - The expression is simultaneously, vacant, haunted, exhausted, and scornful. The face alone doesn't telegraph whether this person is passive or active in his aggression - but there is .
At the end, his journey through the town has inspired him to finally drop the facade and reveal himself to be overflowing with malevolent intent and manic glee at the prospect of murdering
anyone: A monster hiding in plain sight; just waiting for a trigger or opportunity to act out the violent fantasies he normally keeps to himself and attempts to mask.
