It was 2008. Hideo Kojima was supposedly "done" with the series for the fourth or fifth time. Everyone was staring at their chunky fat PS3 consoles, waiting for the blue-tinted disc to stop installing those massive data chunks between chapters. Then it happened. Old Snake, literally crawling on his hands and knees through a microwave hallway, eventually finds himself back at Shadow Moses. But we weren't just there for nostalgia. We were there because the Metal Gear Solid 4 Metal Gear combat sequence was about to break every rule the franchise had established over two decades.
Typically, in this series, you are the bug. The Metal Gear is the boot. You spend hours hiding in lockers or under cardboard boxes, praying that the giant nuclear bipedal tank doesn't see your pixelated head. But Guns of the Patriots flipped the script. It put you inside the cockpit.
The Technical Magic of Shadow Moses Redux
Most games today use massive patches to fix day-one bugs. In 2008, Kojima Productions was trying to figure out how to cram a cinematic masterpiece onto a single Blu-ray. When you finally pilot Metal Gear REX, it isn't just a gimmick. It’s a mechanical payoff. Honestly, the way the controls shift from a third-person stealth-action game into a heavy, clunky, but strangely responsive "mech brawler" is a feat of game design that often gets overlooked in the "MGS4 is just a movie" discourse.
You feel the weight.
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Every step REX takes shakes the controller. The HUD changes to that iconic green-tinted tactical display from the first game. It’s fan service, sure, but it’s high-effort fan service. You’re using a machine that was the "final boss" ten years prior to fight a sleeker, faster version of itself. This wasn't just a boss fight; it was a generational clash between the 1990s and the 2000s.
Why Metal Gear REX vs. Metal Gear RAY Matters
There’s a specific reason why the Metal Gear Solid 4 Metal Gear duel is the emotional peak of the game. It’s about the machines themselves. REX was designed for stationary nuclear launches. It’s a tank with legs. RAY, however, was built specifically to hunt and destroy other Metal Gears. On paper, Snake should have lost in thirty seconds. Liquid Ocelot is piloting a machine designed to kill yours.
But Snake has the "will of the pilot" or whatever thematic shorthand Kojima was using that week.
- The Gatling Gun: Useful for keeping RAY at a distance, though it overheats if you’re greedy.
- The Anti-Tank Missiles: These are your bread and butter, but they require a lock-on that feels agonizingly slow when a giant robot is charging at you.
- The Laser: It’s the "super" move. Cutting through the environment and RAY’s armor feels incredible.
The fight works because it isn't a "press X to win" cinematic. You can actually die. You have to manage your heat levels and your distance. If Liquid gets too close, he’ll use RAY’s hydraulic cutters to shred REX’s "street-fighter" armor. It's a dance. A very loud, very metallic dance.
The Sound of Cold War Relics
Let’s talk about the audio. If you play this with a decent pair of headphones, you notice the sounds of grinding gears. REX sounds old. It sounds like a machine that has been sitting in a freezing hangar for nine years. Which it has. Contrast that with the organic, shrieking "scream" of the RAY units.
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The sound design team, led by Sotaro Tojima, did something brilliant here. They made the machines feel like characters. When REX roars, it’s a mechanical grinding sound. When RAY roars, it sounds like a dying whale. It reinforces the idea that the technology in the Metal Gear world has moved from "steel and wires" to "nanomachines and artificial muscles."
Snake is an old man in an old machine. Liquid is a "reborn" man in a cutting-edge predator. The subtext isn't even subtext; it’s screaming at you through the 7.1 surround sound.
Addressing the "Too Many Cutscenes" Elephant in the Room
People love to complain that MGS4 has more cinema than gameplay. While the ending cutscene is famously longer than some feature films, the Metal Gear Solid 4 Metal Gear segments are where the gameplay actually justifies the wait. You can’t get that feeling of scale from a 2D sprite or a quick-time event. You need the physics. You need the three-dimensional space of the Shadow Moses docks.
The "Old Snake" era was defined by the transition from the PS2's limitations to the PS3's power. This specific battle was the benchmark. It showed that the Cell Processor (which was a nightmare to develop for, just ask any dev from that era) could handle two massive, highly-detailed models colliding without the frame rate dropping into the single digits. Mostly.
Tactical Advice for the REX Pilot
If you’re revisiting this on an emulator or (hopefully) a modern collection soon, don't play it like a shooter.
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- Use the Kick: Most people forget REX has a physical melee attack. When RAY gets in your face, a well-timed kick creates the gap you need to fire the laser.
- Watch the Knees: RAY likes to go for low sweeps. You have to stay mobile, which is hard when you’re driving a 500-ton bipedal tank.
- The Laser is a Sniper Rifle: Don't just fire it. Wait for the animation where RAY opens its mouth or readies a charge. That’s your window.
It’s easy to get overwhelmed by the scale, but the AI is actually quite predictable once you realize Liquid Ocelot is trying to show off. He plays aggressively because the machine allows it. You have to play defensively because REX is a relic.
The Legacy of the Duel
We haven't seen anything like it since. Metal Gear Rising: Revengeance had Raiden throwing Metal Gears into the sky, which was cool in a "Rule of Cool" sort of way, but it lost the weight. It lost the mechanical grit. The Metal Gear Solid 4 Metal Gear fight was the last time the franchise felt like it was grounded in some kind of weird, alternate-history engineering.
It was the end of an era. Literally. After this, the series went to the 1970s with Peace Walker and then the 1980s with The Phantom Pain. We never got to see the "future" of Metal Gear again. We stayed in the past. So, this fight remains the chronological peak of the timeline's technology.
What You Should Do Now
If you want to experience the best version of this, you’re currently stuck with a few options. You can dust off a PS3, which is getting harder as the hardware fails. You can try RPCS3 on a high-end PC, which finally runs MGS4 quite well if you have the CPU cores to handle it. Or, you can wait. Rumors of a Master Collection Vol. 2 are everywhere.
Next Steps for the Metal Gear Fan:
- Check your save data: If you still have a PS3, look for your "Big Boss" rank saves. Replaying the REX vs RAY fight on Extreme difficulty is a totally different experience than Normal.
- Study the models: Look up the Art of Metal Gear Solid 4. The internal schematics Kojima's team drew for REX's cockpit are insane. They actually thought about where the pilot sits and how the pedals work.
- Watch the "Making Of" documentaries: There is a great segment on how they choreographed the REX vs RAY fight using motion capture actors pretending to be giant robots. It’s as ridiculous and awesome as it sounds.
The Metal Gear Solid 4 Metal Gear experience isn't just a boss fight. It’s a funeral for a certain type of game design. It’s loud, it’s clunky, it’s over-the-top, and it’s arguably the most "Kojima" moment in the entire franchise. Don't skip the cutscenes leading up to it. Let the tension build. When that "REX" prompt finally appears on the screen, you'll understand why this game, despite all its flaws, is still a masterpiece of the medium.
Go back and play it. The mechanics hold up better than the nanomachines lore does, honestly. Just watch out for the missiles.