The most effective starting strategy for the Inferno faction.

Yes, I also start by getting the old Cerberus upgrade; I think it's the most sensible option because, in the beginning, we mainly fight neutral creatures in groups of up to 3, and we don't really need the fire breath. The old Cerberuses are about twice as good in terms of stats (definitely in terms of damage). Furthermore, why upgrade Imps? Because their damage increases significantly. At the beginning of the game, un-upgraded Imps are useless, neither as meat shields nor as damage dealers, so we upgrade Imps first, and last (after Cerberuses), I think we should upgrade Demons, because their main task is to distract. Also, in the early stages of the game, the new upgrade cannot effectively perform the jump attack because if we want to keep them alive, we need to remove the retaliatory attack, and we can only do that when the gates are upgraded, because then we can summon Cerberuses as well, and the number of summoned creatures will be greater.