i'll just leave the thing alone since both of them have radar
No they don't. Only the nanosuit seems to use radar. The Chief uses a motion sensor, which uses completely different systems than radar. Radar works by emitting low-frequency waves and anolyzing the times it takes for the waves to bounce back via the Rayleigh Scattering Effect. Motion detection works by other means, usually geomagnetism, sound disruption, or infared. In case of Chief's motion sensor, it's most likely infared, since one of the Spartans in Halo: First Strike disassembled his suit's motion sensor, which utilized a quartz mirror.
Basically, my point is that there's no suit module that can counter the motion sensor and therefore nothing that Alcatraz can do to avoid that sensor, other than standing still or staying out of range of the sensor, which has a detection radius of around 45 feet.
and again nanovision will see him a lonway off before hes even on his motion sensor...
Which won't help him at all.
from what ive seen in the game spartans ain't that hard to take down
Neither is Alcatraz.
... can you deflect a missile in game... no and they are propelled by rockets ... if ur talking about the shorter ranged ones...
Rockets, missiles. Potatoe, Potato. Same thing.
all that stuff said about master chief is a load of crap if it doesn't do anything in game...
It's not crap. It was in the book, and since it was officially part of the Halo universe it's therefore canon. Except for the Halo Legends anime show, that's just stupid.
heck in mw2 you can slow down time probably thanks to adrenaline(or something)
MW2 is by far one of the most unrealistic things I've ever seen. Apparently, normal human beings can instantly regenerate bullet wounds and can fire Barret M82 fifty-cals with high-precision standing up with no problem, obviously disregarding the fact that the recoil from an M82 is strong enough to shatter a person's collarbone if held the wrong way. So don't take examples of human feats from MW2, or any COD game for that matter.
also first nanosuit had speed mode

So does Spartan armor. You can equip the suit with an armor ability than enables to sprint as well.
dont forget gauss rifle and x-43 mike...
Don't forget Fuel Rod Cannon and Focus Rifle.