Darksiders II = $16.98 / £11.88
Darksiders II Season Pass DLC = $6.80 / £4.42
Both use Steamworks.
You can use the Redeem code G2PO to get an extra 5% back in blue coins (That’s the GamersGate rewards program. Collect enough coins and you can get a free game). Only works on one game per order so make two transactions if you want both.