Chromehounds

This is awarded for completing all 7 missions in the Soldier Arc of the Story Mode. After learning the controls and strategies the missions got very easy for me. Keep in mind you do need to obtain an S Rank in all Story Mode missions for the Tact. Instructor achievement. Here are some very useful guides for S Rank I found on GameFAQs (Credited here: https://gamefaqs.gamespot.com/xbox360/928456-chromehounds/fa...)

Mission 01: Soldier RT Training
Basic Mission: Follow the commanders instructions as he gives them to you.
Your final grade will incorporate Time elapsed, Enemies destroyed, and
Average attack distance.
Extra Operations: "Real" Combat in <3 Mins
Tips for S rank: Just make sure you get all of the enemies in under three
minutes, once 'real combat' starts. To make it easier, they come in from these
points: D4, E4, D3, and G3. With the exception of D3 (a lone tank) the others
will be mixed squads of tanks and AT-ST's, with a single heavy walker in the
final group.

Mission 02: Wipe-out Rebels
Basic Mission: Attack and destroy the rebel base camp in grid C2, wiping out
all enemies along the way. Your final grade will incorporate Time taken,
Enemies destroyed, and your average attack distance.
Extra Operations: Enemy annihilated
Allied scout survives
Tips for S rank: Start attacking as early as possible, which protects the
scout by making sure everyone comes after you instead. Then it's just a case
of mopping up the small force in G3 (four tanks and two AT-ST walkers), and
two more tanks and AT-ST on the river side. The base is defended by three
heavy walkers outside, and a good many tanks inside. Be sure to get them all,
it can get a bit confusing once the buildings start falling.

Mission 03: Wipe-out Rebels 2
Basic Mission: Attack and destroy the transport with an enemy officer in it.
If he gets too far away, you will fail this mission.
Extra Operations: Halt enemy before F4
No damaged parts
Tips for S Rank: It can get a bit hectic, with lots of fire coming in to you,
but ignore it all, and focus on the little APC like vehicle flanked by two
AT-ST. He starts in grid E6, and moves East, over the hill. As soon as the
buildings end, get off the road, and start shooting at him. Just look in
front of the two AT-ST's to find him. it's easy, but may take a couple of
times thorough to get a feel for it.

Mission 04: Wipe-out Rebels 3
Basic Mission: Attack and destroy the rebel headquarters in grid G7, and
secure as many COMBAS towers as you can.
Extra Operations: No damaged parts
Time spent <5 Mins
Tips for S rank: Take out all the enemy units near to where you start, and
head to COMBAS tower G (you don't need to capture it, or any others). Move up
and over the hills, heading straight for the base, taking the narrow left path.
Watch for the tank squadron just over the brow, it can be hard to hit them
because of the gradient. Take out as many enemies as you can, but head straight
for the base. Start shooting it as early as possible, cycling through your
weapons. You need to level all the large, main buildings, the oil refineries
and the cylindrical tanks. Watch your leg damage, as even with just tanks it
can mount up. Keep shooting, keep moving. It's not too hard, but it does
require a little luck and good shooting.

Mission 05: Defend Tarakian Base
Basic Mission: Push through the advancing enemy to safety, completely
destroying them in several locations.
Extra Operations: All allied units survive
No damage to Silvys ACV
Tips for S rank: Not too hard. Just head to all the locations as quickly as
possible, and take out the enemy as efficiently as you can once you are there.
Always shoot first, even if you know you won't hit, as you will draw the fire
away from your allies, and bear in mind that for the very last group (heavy
cannons) you are going to have to sprint almost the length of the map!

Mission 06: Defend Tarakian Base 2
Basic Mission: Head to the enemy base and destroy it.
Extra Options: No damaged parts
No damage to Silvys ACV
Tips for S rank: This can be a bit close. Keeping Silvy damage free is the
main hassle, but it's easy enough with a bit of practice. As soon as you
start, head forwards, and take out the three Heavy Walkers attacking the base
in B1. Then get on the road, taking care of the little hover scouts that
approach. Follow the road to about F3, when you should see, to the left,
in the distance, three Heavy walkers, just over the brow of a hill. Head
to them, and kill them quickly, before heading straight for the base (H6).
Keep an eye on the road, and take out any AT-ST as they appear (they endlessly
re-spawn), also keeping an eye out for the three snipers dotted about, they
can cause you problems if you don't identify and kill them quickly. Once at
the base, take care of the two heavy walker defenders, and then stand just
out side the base's bay area, and fire your small bombs directly into it,
hitting the main tower with your other weapons as they recharge. Kill any
AT-ST as soon as they fire on you, or if necessary, use the base as cover
while they get close. Success depends on a nice balance of killing everything
along with quickly getting to and destroying the base. Don't be afraid to
replay the level just to learn where the enemy moves from and to.

Mission 07: Mop up Rebel survivors
Basic Mission: Single handily destroy the last remaining Enemies; a Commander
and Defender HOUND.
Extra Options: No damaged parts
Enemy hound destroyed in <3 Mins
Enemy annihilated in <5 Mins
Tips for S rank: Cross the river and take out as many tanks as possible. A
little further along, from around the cliff in H2, the Command mech will
appear. Draw him in to you, constantly firing at his cockpit. He shouldn't
present too much of a problem, but once he's down, the slower Defender HOUND
will be in range. His long range attacks are devastating, and he's Armored
on the sides, but he's not very mobile, so weave in close to him and give
him everything you've got. Watch for him to pause; a sure sign he's going
to let rip with him massive cannon.