Is Intel Iris 1536 MB ‘better’ than Intel HD Graphics 4000?
Solution 1:
There are 3 types of mid 2014, two with integrated graphics & one with a discrete card.
The integrated chip is Intel 5100 or 5200 so yes, well within spec, even if you don't have the dual-graphics version with a GeForce GT 750M.
Source: Everymac
Solution 2:
Yes, the Iris Pro should be enough for the game. The HD 4000 is included in the Mid-2012 MacBook Pro so yours is newer than it, so definitely will work.