MArcomage

Useless card. 21 damage is too small for 16 bricks and 10 recruits. For example, Griffin (10 recruits) and Obsidian gargoyle (15 bricks) make 27 damage together. Griffin have Far sight, Beast and Alliance. Obsidian gargoyle can reduce enemy quarry by 1.
I suggest one of 2 variants of balance fix:
1. Increase damage to 25.
2. Decrease recruits cost to 5.

As it is now, it's very effective in an Unliving deck that otherwise doesn't have very many cards that can hit so hard. Since you're likely to use it at a time that it triples your bricks production, you can relatively ignore most of the bricks in its cost. Since few Unliving cards use recruits, the recruits cost isn't a large factor, either.

As someone who plays Unliving occasionally, I have to argue that this card does not need to be made easier to play. I can't say how it would go in any other kind of deck.

I also wouldn't compare its damage/cost ratio to two cards that cannot be played in the same turn. That extra turn comes at a cost that can't be calculated numerically.

Iron golem is worst attack card in game. 21 damage for 26 resources. Unliving is not so powerful keyword to pay so much for it. It costs 10 recruits!!! For 16 recruits Black unicorn makes 25 damage (or makes 15 damage and raises lowest facility by one). Iron golem used not only in Unliving deck. It can be used in rush deck. For example, standard deck 1 contains Iron Golem. Also I think Unliving deck is not very powerful now. So this card can be improved to improve balance. After last update packs new good attack cards added (for example, Black unicorn) and old attack cards improved (Ghoul make 13 damage for 5 recruits and 5 gems). So Iron Golem is not good card in attack decks now because there are more cheap and effective attack cards. Iron golem is old card and not changed since 2007. I think it is time to improve Iron Golem now. I suggest additional variant of balance fix: Unliving. Enemy wall: -6. Attack: 21.

I'm playing unliving lately and i must say this card is pretty useless in that deck.
I mean, unliving deck wins by cosrtuction (but there is also a variant with orc regiment) and Iron golem is used only to lower enemy defense if he try to win by tower construction, but there obvious better card to use (sabotage, catapult, orc regiment itself).
I agree, the card needs a change. it could raise your wall, lower enemy wall (as harmonius suggested)
or other. My suggestion is that it doubles your unliving token so that it's easyer to get the unliving bonus.
Or a simple cost/damage adjustment it's fine too.

Now it is even more hard to use Iron Golem. And no reason to use it for small 21 attack. Old resource variant 16B 10G was unique, it could be played in first turn of second player.
Maybe next variant?
15B 10G
Attack: 20
Mode1:
Bricks: +6
Mode2:
Recruits: +4
This variant can be played in first turn of both players and gives resources for next turns.

I think that a lot of the value of the card comes from, as harmonius noted, its ability to be played on the first turn, putting the opponent on the defensive from square one. 21 is enough to ruin the initial wall and allow further strikes to directly hit the tower. I do not have a problem with this card as it is.