Obviously on a purely technical level, I stand in awe and envy of this piece. A great composition overall.
This having been said, I feel like it's sort of more than a nit-pick to say that the Hulk's face looks awfully human here. Artistic license, I know, but 99% of the time, he has a somewhat inhuman set of facial proportions; a tiny little stub of a nose, broader-than-human horizontal proportions, etc. The face here just sort of looks like a green dude.
And again, a fantastically-rendered green dude, drawn with a level of skill I can find no fault with. Just one that seems off-model to me.
MARK WAID (W) • MATTEO SCALERA (A) Cover by MUKESH SINGH Time Travel Variant COVER by TBA
"TIME TO SMASH" PART 1!
• Spinning out of the events of Age of Ultron! Hulk’s sent on his most dangerous mission yet, working for a secret subdivision of S.H.I.E.L.D.! History’s breaking--and only the Hulk is strong enough to hold it together!