the IR is not harder or easier than the CPL(it cost more!). IR is just new, making you believe it is harder as you have minimum experience . I think IR is easier cuz you have to rely on your charts and everything is on your knee bord and it required lot of anticipation which make the difference between a pass or fail.
you can fail a CPL by not keeping space with another traffic when in IR, you dont see anything from the window.
IR tests required an ILS, NDB, one engine traffic pattern and land and some other basic handling excercice.And don't forget to say the famous "ANY ICE?" for each 1000 feet.