Hey guys, after snooping around the net myself, I coudn't really find a way to get these achievements, I played for about two hours and still didn't get it ''Living Loving Bug'' But eventually I found an easy way to get all the achievements, so I'm creating a mini-guide to help you out!
One and Done - 30 G
Score the winning point in a game of Keepaway against Legendary AIs.
This is best done on the 1 vs 1 map Chasms. use the Arbiter for this one. Set the AI to Legendary of course, and have Captain Cutter be your opponent.
As soon as the game starts, build a Temple, and three supply pads. Scout with your Ghost for supplies, there are alot near your base, and about 60 to 90 supplies in the center, collect those with your Ghost and move The Arbiter to the center of the Map and wait, while you wait, you can build a fourth supply pad, there is no need to upgrade to a Citadel.
By the time the Sentinel spawns (the Flag), you can almost instantly grab it with Arby. Grab it, and go camp at the back of your base, and wait. You will notice a timer running, that is how long it will actually take for capture the flag completely and have a point added to your score. You need three points to win.
Upgrade one of your supply pads every now and then, in case Arby needs to get into rage mode, but personally I never had to do this.
Now, when the timer passed and you are rewarded a point, go back to the middle with Arby. Give him the upgrades ''Fiendish Return'' and '"Defiant Rage'' if needed, found at your Temple, and wait for the Sentinel and capture it, again camping at the back of your base. Repeat one more time.
Cutter will almost never send his units to you, he will be too busy building up his base. But if you really really want to be sure, listen to the AI what kind of units Cutter makes, and build two turrets at the front to counter appropriately.
You will be rewarded the achievement after Three Sentinel Captures.
Pull Hard, Pull Deep - 20 G
Win and never trail in a Tug of War game.
Again, play as The Arbiter, with your opponent being Cutter and the AI set to easy. Choose the map Chasms Build a Temple and two supply pads ASAP, and have your Ghost attack the enemy base ASAP as well. Destroy the Warthog, so it cannot gather supplies. Follow it if needed. When the warthog is gone, have the Ghost attack the (probably only) building the enemy has, (Make sure it's a reactor). By this time your Arbiter should be ready and on his way to help destroy Cutters base. If Cutter starts to build supply pads, focus all your attention on that, do not give him a chance to get supplies. MAKE SURE HIS SUPPLY PADS DO NOT COMPLETE BUILDING. If he starts building something, have Arbiter trash it up before it completes! If the enemy Warthog is destroyed, and the enemy base as well, you are victorious and are granted this achievement.
Freak on a Streak - 20 G
Gain at least 15 population from a single wave in a Reinforcement game.
You will most likely get this the same time as ''Living Loving Bug'' As a Scarab takes up 20 population. If not, then just have alot of supplies and population free and hope for the best. If you need to get rid of units, use the ''Prophet Cleansing Beam'' Method described in the help for ''Living Loving Bug.
Living Loving Bug - 30 G
Get a Scarab during a Reinforcement game.
Play as the Covenant, preferably The Prophet Of Regret, set your opponent to be Captain Cutter.
Set the opponent A.I. to easy, to make it easier for you.
Build supply pads only, upgrading them, and a temple, and upgrade your ages (Upgrade found at the Temple, Age of Doubt first and then the Age of Reclamation) so you get Tech Level (The lightning bolt in the top-left corner) to Three, this will require two ''Age'' upgrades. Also, Capturing a Second Base is almost mandatory and increasing your Population (This Upgrade can be found in the Temple as well) helps as well
Kill any unit you might get using the Prophets cleansing Beam if your population is over 20.
Make sure you have enough population room and enough supply to ''Buy'' a Scarab. I know you can't buy units, but you need the supplies. So have 4000 Supplies in reserve and 20 population available.
Hope you get a Scarab instead of alot of Wraiths or anything else. If you have too much units and they take up too much Population, Prophet's Cleansing beam is your friend. Kill your own units with it if needed.
Hope this guide helps you out!