You will notice that there is no absorber in this set, so we skip that step and move on to searching for key units.
Perforator cannot be the brunt of your attack force because such a strategy requires you to buy Animuses continually to power them. If you want to see why this doesn't work, go into analysis mode in base+Perforator and play one side using Perforators as attackers while the other side uses Tarsiers. The takeaway is that Perforator is just not efficient enough when you have to buy Animuses to power it. It's not a key unit. It's usefulness is mainly as a red sink. Actually it's also quite a good preemptive defender when you consider that in the late-game red is often spent on horribly innefficient things like Rhinos for soak or even gets outright wasted - it's then like buying two Engineers (that also generate 1 threat) for just 3 gold.
Shadowfang is a permanent attacker, and is one of the most efficient ones in the game in fact. It's full-turn inflation is 1.51, so definitely a key unit. The problem with Shadowfang in most sets is two-fold: first, it costs 3 red, which means you need 2 Animuses to get it, and that means you're probably wasting the 4th red a lot of the time. Second, and this is just a problem with heavy red units in general, is that red is often difficult to spend once the game reaches a point where defense is all you can afford to think about. The presence of Perforator, however, nullifies the first problem and to an extent the second as well, which is generally enough to make Shadowfang at least worth considering. Still, we'll see if any of the other key units look better before making a decision.
Another permanent attacker, but not nearly as efficient as Shadowfang. Iso Kronus beats BSO by itself, but is definitely one of the weaker key units in the game, so we should generally go for it only if nothing better is available - especially considering that synchronized attack pretty much sucks when there is preemptive defense like Perforator.
Cryo Ray is extremely powerful, but like other chill units, it is not key. Notice something about it and Iso Kronus though? The problem with a fully-synchronized Iso strategy in most sets is that you have to delay your purchases by one turn every other turn so that you keep them synchronized. Cryo Ray solves that problem: if you have two Conduits, you can buy two Iso Kronuses every time they fire and two Cryo Rays every time they don't fire. You can get the full power of synchronized attack (absorb denial) without being penalized in efficiency. This makes Iso Kronus significantly stronger.
Blood Pact is a fairly weak unit in general even after the recent buff it got, but in this set it has some advantages: against an opponent playing a fully synchronized attack strategy, the Grimbotches you give your opponent will only deal damage every other turn (either that or they just sacrifice them early). Additionally, if you buy Cryo Rays you can freeze the Grimbotches on their last turn. This makes Blood Pact actually quite good if your opponent is trying to go Iso Kronus/Cryo Ray. It's also a soft combo with Shadowfang since it thrives on high inflation, and Shadowfang, being such an efficient attacker, naturally shoots inflation through the roof.
Apollo is not an attacker. It does destroy enemy units in its own way though, so it can very well be your strategy. It also makes a point of being an extremely hard counter to certain units, such as Shadowfang. However, Apollo commits you to three Blastforges, which is not something you want to get if there are no other blue units. Apollo actually loses to base set-centric strategies without support.
So we see two different strategies here: Perforator Fang and Cryo Kronus. Perforator Fang is hard countered by Apollo and Cryo Kronus is hard countered by Perforator and Blood Pact. Is this another base set attackers game? No, actually. Apollo isn't viable without support, remember? That means you can actually use Perforator Fang here because if the opponent commits to Apollo before you are committed to Shadowfang, you can just bail out and make a base set transition, and if they wait until after you have already bought Shadowfangs then they will probably be locked out of Apollo by then. This is therefore a Shadowfang/Perforator game with Cryo Ray and Blood Pact available as support units.
*Credit to phufhi for help with the analysis work that went into rejecting a past version of this article.