I understand. But as a universal tool for defeating elementals, especially on Impossible difficulty, where you usually barely have enough resources for one hero on the first day, I wouldn't recommend it. It all depends on the map. In Beltway, as far as I remember, you start with two heroes, and there are chests, so you can take advantage of that.
Everyone was surprised how it was even possible to get green dragons on the first week.
Some even asked for a step-by-step guide – if you're interested, look it up.
So, nothing is impossible.
And regarding the first day – if you start with a Warlock castle and build gargoyles... how many more units and gargoyles will we have? ;)
