Yeah I played on Xbox. The only time I used the knife (outside of using it defensively) is the very beginning of G1 since he's stuck in the opening animation for a good chunk of time.
I took a brief overview, and I feel I won't have trouble doing this - but my only issue is the sewers and the G-Adults. Do you have a general strat for when you encounter them - especially the tunnel before the flamethrower?