The first thing we do when we look at this set is ask "what will our absorber be in this game?" In base set, the best absorber is Wall, but this set has Centurion. Centurion can absorb 3 more damage per turn than a Wall and can attack for 2 at the same time. This means absorb is extremely powerful in this set, which justifies a very large economy. You should probably get about 23 Drones in this set - definitely get a third Engineer on turn 2.
The next thing we do is pick out key units. Of the remaining four units, which are key?
Militia is a permanent attacker, which key units usually are. But is it really better than base set attackers? It costs the same as a Steelplitter and does the same amount of damage. Steelsplitter is one of the least efficient attackers in the game, having barely higher inflation than Drone. So Militia is not a key unit. It's still a decent first attacker since it can click to deny absorb when your opponent puts out a Wall, but you definitely won't be making an army of them.
Grimbotch is an attacker, and it is highly efficient, but it is not a permanent one. It does not ramp your attack. That doesn't mean you won't be using Grimbotch here; on the contrary, this is definitely a unit you want to buy several of, you just don't want to start with it. Once you have a respectable amount of permanent attack the short-term will begin to matter more and more relative to the long-term, making Grimbotch an excellent purchase.
Cynestra is a permanent attacker. But does it have the same problem as Militia (not being any better than the worst of base set attack?). Calculate it (if you don't know how to do this, see my math article) and you will find that it has a full-turn inflation of about 1.5. Now that's what we call an efficient attacker! Sounds like Cynestra is a great thing to make an army of here.
Gauss Charge is a tech sink unit, not nearly efficient enough to be something you 'go for'. By all means buy it if you have extra green, but it's definitely not the center of your strategy.
So now we know our strategy in this set: get lots of Drones so we can overcome the absorb barrier quickly, then start making as many Cynestras as possible, and spend extra red on Grimbotches. Normally getting three Conduits in order to produce a Cynestra every turn is questionable because you might have trouble spending the green once you can no longer buy Cynestras, but here you can always sink excess green on Gauss Charges, so don't be afraid of getting three Conduits. Finally, remember to get up a Centurion when your opponent's attack gets above 4. You should now know basically how to play this set.
As for what specific opening to go for, I would recommend Econ Blastforge for player 1 and Econ Blastuit for player 2, both into getting a Militia and three more Drones, probably dropping the Animus the turn after.