There are a few things that always bugged me about Spidey (pun intended). How is he able to cling to surfaces when his skin (which does al the sticking) is covered by his suit and how does he keep that full body pyjama costume hidden under his clothes. That's why I tried to made his costume a bit more functional. With open hands and feet and a bit more open neckline (Peter Parker can't be wearing turtleneck sweaters all the time). I also tried changing the colour scheme (because red/blue didn't really seem like colours that you would directly link with a spider) but everything i tried looked weird. In the end I just decided that the original colour scheme was to much a part of the character to change so I sticked with this (pun intended, again).
I had to google Tarantula (didn't know the character) but you're absolutely right, they do look a lot alike I think it's mostly the mask, maybe I'll tweak it a bit
Good luck! I do like the design. I just thought you should know, because that might be something the judges notice. On the other hand they might not care if the two look similar.