I smiled as I read that.
Good analysis! That makes the ending even better for me, thanks!!!
My whole analysis is this.
Venom realises who he really is before we see it on screen, it seems to me like he uses the tape TMWSTW as a motivational tool. We see venom feeling his face in the mirror, whilst looking at his old face, he knows deep down that he's not Big Boss but he goes with it as that's his job, his role as the phantom. he was meant to die and thanks to Big Boss he was given a second chance, thanks to him Big Boss was given a second chance.
We see Venom take out the tape and he takes a while to put it in the Walkman, he's getting ready to psych himself up, get into his "role". We eventually see Venom put the tape into the Walkman and press play, while listening we get to see Venoms facial reactions, when Big Boss says to Venom that from here on out Big Boss, he smirks and straightens his back and head, giving off the sense that he's motivating himself and he's enjoying every moment of it.
The line Big Boss say "From here on out, you're Big Boss" echoes what Ocelot says to Venom, "From here on out, you're on your own". This is the opposite to what Big Biss says moments before, when he says "we are both Big Boss, no, he is the both of us together" it's basically Big Boss saying, everything you've done is on your toes, you've played your part and now your on your own, whatever happens next YOU'RE Big Boss, not me.
We next see Venom flip the tape, it reads Opertation Intrude N313. We all know what this is and what happens during the Operation, it leads to Venoms death. The way he flips the tape, surveying the writing on it, it seems like this is the first time he's realising what to do with it, or maybe not judging by the count on the top right of the Bitcorder, this tells us he may have been reading the data bit by bit, step by step, using the tape to build Outer heaven. He's not seen or heard the full length of the tape, but he's about to now.
He puts the tape in the Bitcorder to be loaded by the MSX, we see and hear the tape being loaded and a blue light comes on. The camera pans back towards the mirror, still with the blue light shining across the room, venom walks across the screen back towards the mirror, as he does so, he blocks the whole view of the camera, exactly like a transition from one scene to the next. Once the view is clear, there is no more blue light from the MSX and we see Venom in his "Demon" state of mind. As we know, he does this in the game if he acts Evil, or his mind turns "Evil".
To me this and the fact the MSX is now turned off tells us he's either read or heard the data on the tape and what it contained has made him turn evil. He knows his time as Big Boss is up and death awaits him when he walks back through the doors.
Venom punches the mirror, clearly in anger of what the end of the OIN313 tape contained and we see the real Big Boss behind it, to me it signifies that their goals have "clashed", Venom clearly doesn't agree on how his role ends. At this moment we see the Outer Heaven Insignia behind Venom on the wall, something which before he punched the mirror was a DD insignia, this is further evidence that their goals have clashed. We then see venom turn and walk away from Big Boss, once again telling us he's not willing to die for Big Boss's goal.
But, it's too late, the plan is in Motion. He walks away into the unknown, to his death at the hands of Solid Snake.
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