If you have not gotten this one dose yet, I would say I would go with a dark contrast Black and grey shaded version.. and maybe a hint of color for the space marine eyes and the Chief's visor. I think that would offer a very dramatic effect and completely capture what this picture is trying to embody... but that is just me.
Well, once you think about it realistically. Not only is a Space Marine bigger, stronger and tougher but he also has a technological advantage as well. I mean just look at Bolter for example, it's a large, .75 calibre assault rifle. It has a much greater mass than most standard-issue rifles such as the Halo assault rifle. Unlike most rifles, it lacks a stock, resulting in a grip much like a pistol's or a submachine gun's. A Space Marine's bulky power armour would make shouldering a stock an awkward experience, but power armour is most likely also able to compensate for vibrations and oscillation, making a stock redundant. Stocks are sometimes used, however, with an extended barrel and an M40 Targeter System to transform the bolter into a sniping weapon system. These sniper-bolters are most often used with Stalker Silenced Shells.
The standard Bolter ammunition is designed to penetrate the target and then detonate, causing immense damage to the target and leaving little opportunity for survival.
You'll notice (if you peer closely) that the marine's head is at 8', but you should also see that the soles of his feet are at 1' making this illustration (by its designer, Jes Goodwin, also pictured) exactly 7' tall.
You can also interpret it as Chief hitting the Space Marine with his grav-hammer, which is a 1 hit kill. Master Chief hijacks tanks and fights off Hunters, we all know he could beat a regular Space Marine, even a Terminator if he's lucky.
How can I put it. Well, in a way Space Marines, are like hunters in Halo (note: hunters don't die in one hit by gravity hammer), but they move as fast as Spartans, some have centuries of experience, their internal organs and such are replaced and superior, along with their blood, mental condition, cybernetic implant, some can have psychic powers, heck! Some can spit acid. They are more advance in technology, than Spartans ever will be.
Plus: This is not a ordinary Space Marine, he is a Blood Angel, the most crazy and bloodthirsty of all Space Marines chapter.
the grav-hammer is a one hit kill weapon in Halo, space marine power armor (and surely tactical dreadnought armor) are superieur towards most, if not all, suits of armor within Halo. (about 38000 years more advanced). It has stimulants, meds, chems and automatic protectors that keeps its wearer alive even after being hit by power weapons, severed arteries and the likes. the powerfist, just like any other power weapon, completely ignores armour and doubles the strength of it's wearer, who's strength is more than enough to smash through a tanks armour even without doubling it. I think that master chief will die a horrible death.
Since you put it that way... master chief totally looks like Kasrkin commando The thing I dislike however about it - those guys are on the same side, fighting for humanity, not against it. Insert a chaos marine instead. Good work btw.
Well to put it simply I don't really like chaos that much also Blood Angels are one of my favourite chapters and one of the first armies I ever collected which I started as a kid, plus we all know Blood Angels are blood crazy so why not pick a fight with Masterchief.