Robert Downey Jr. actually wore a full Iron Man Mark 1 suit in 2008's Iron Man, but it presented some physical challenges while acting.

Tony Stark's original suit of armor in the MCU's first Iron Man movie may be iconic, but it was also incredibly difficult to use while filming. The many Iron Man suits Tony Stark wore throughout the Infinity Saga gradually evolved in terms of technology and comfort, but they also became less and less realistic. The bulky Iron Man Mark 1 armor seemed like something a real-life scientist could make in a cave and with a box of scraps, while the Iron Man Mark 85 suit was the height of sci-fi in the MCU's Infinity Saga due to its nanotechnology and energy shields.

It naturally made more sense to rely more on CGI as the Iron Man suits evolved. But in the beginning, the Iron Man movies used a great deal of practical effects. It was normal to see Robert Downey Jr. and his stunt doubles wear part of the Iron Man armor, if not the whole gear. The practical Iron Man suits were remarkably uncomfortable and far from useful for any semblance of physical combat. One specific suit, Tony Stark's first Iron Man armor, the Mark 1, presented many challenges for the people who had to wear them.

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In the behind-the-scenes documentary that accompanies 2008's Iron Man blu-ray, stuntman Oakley Lehman describes the Iron Man Mark 1 suit as “close to a hundred pounds." Lehman actually wore the whole armor, which was even equipped with functioning flamethrowers that at one point set the suit on fire without the stuntman even realizing it due to how thick and heavy the suit's material was. Coupled with the limited visibility and movement inside the suit, the stuntman found it difficult to deliver an accurate performance for the camera. Lehman said that “what it feels like you’re doing inside the suit doesn’t relate at all” to what viewers ultimately see onscreen. When the MCU's Robert Downey Jr. wore the armor himself for the first time, he said that just practicing the movements for a while took a toll on his body.

What's special about Iron Man's Mark 1 suit is the level of commitment from director Jon Favreau, producer Kevin Feige, special effects legend Stan Winston, and the rest of the team behind the movie, who made their best efforts to make Iron Man as realistic as possible. This was a time before the MCU was even a thing, as the crew in the behind-the-scenes documentary express how they hope to start a franchise after Iron Man's success. Without the fanfare that all of Marvel's MCU movies have gained by now, the level of detail in the Iron Man Mark 1 armor and all the hard work it entailed are especially praiseworthy.

What's more, the results hold up to this day. Every scene in 2008's Iron Man where practical effects were used are still breathtaking more than 14 years later, and many of them even overshadow some VFX sequences from the MCU's latest installments. If Tony Stark's creation of the Mark 1 armor is impressive, it may be even more impressive to see that it was basically made for real — complete with weapons, lights, and moving parts — just to make the movie more authentic. It all goes to show why the MCU has been so successful since its very beginning. The team's passion for the craft transcends the screen and withstands the test of time.

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Nicolas Ayala is a writer with a passion for blockbusters and big-screen adaptations. He loves all things Marvel, DCEU, and wacky comedies. The cheesier the movie, the better. When not writing, he's probably coming up with new ideas for the next writing sessions.