I've dipped in and out of the X-Men series, though it looks like I've managed to watch all of the first three (apparently without any of them having left a particularly strong positive impression) and I reckon I've seen most of First Class on tv along the way. So I've picked up enough for Days of Future Past's time-travelling bringing together of the two sets of X-men (younger/older: McAvoy/Stewart, Fassbender/McKellen) to make sense, but not been immersed enough for the emotional beats to hit fully home; still, this was good.