You have a solid foundation.
The illustration itself has some anatomical weaknesses in the upper arm - bicep too large, tricep too small. The tricep accounts for 2/3rd the mass of the upper arm, so even on the Hulk his triceps should be that much larger than his bicep.
The torso has some wonky anatomy in the rib cage. The serratus magnus is wrong. Extending too far down to the abdomen.
The legs have some screwy anatomy as well. The vastus lateralis seems to be overlapping the rest of the leg muscles.
It's always best to not over render anatomy if you're not certain. For reference you should pick up Figure Drawing For All It's Worth
and possibly get a copy of Gray's Anatomy at a used book store for anatomy that isn't covered in illustration books.
The inks are solid, but you need to vary your line weight
. Varying line weight can add to the illusion of depth, weight, and lighting. It also helps prevent your artwork from looking like a coloring book illustration.
As for a career in comics - you'll need to put in your 10,000 hours. Any jackass can draw a pin-up (trust me, it's pretty much all I do and why I have a day job
). You need to be able to draw everything - buildings, cars, baby strollers, old people, trains, bottles, kitchens, etc. etc.
Look at the artist working today that you think is the worst and try to draw better than that guy. It helps to start low and work your way up. If you set your sights too high, then you may set an unrealistic goal and become discouraged.
I look forward to seeing more of your illustrations.