Normally I wouldn't say anything about anyones art but since you asked for critiques, I figured I would put my two cents in. I'll also try to be as constructive as possible without sounding like a butthole because I know sometimes people can and it can be very discouraging but know that I mean this as a fellow artist who only wants to help.
Vision is spot on. You have a great idea of what you wanted to draw and you executed it. With that said, technique is lacking a bit. Line weight is very important when drawing, especially when you have two figures offset from each other. I would at the least thicken the outline of Spidey to make him pop out more but like I said, technique goes a long way. Varying line weight is a cool trick that you can use that would definitely make Spidey's left arm pop out at the viewer as well. By Making the lines thicker on the hand and then gradually making them less thick as they get to the shoulder will make it stick out and give the illusion of it flying out out you.
The other thing that sticks out is Spidey's left knee. I can't quite put my finger on what is happening there but it looks like his kneecap is blowing off.
Anatomy reference is not frowned upon in comics, in fact it is encouraged.
Anatomy, if drawn wrong, can definitely make viewers not believe what they are seeing and in comics that is death for artists lol. I recommend checking out some of the pose reference groups here on dA such as Pose-Emporium or dAPoses. Lots of great reference and a lot of it they don't mind you using as long as you link back to the photo. I also have some pdf versions of drawing books that really help me if you want to give them a try.
You did a great job, better than most people I've seen but I would practice line weight and anatomy first. Then maybe take a look at light source studies and play around with extreme lighting ie. filling blacks and hatching, etc. Overall, great job! Just take some time to study the basics a bit more.