When fighting the spider-slayers atop the city buildings. DO NOT use the "Impact Web" because they dodge it with ease and it is almost useless (also refer to LATER MENTIONED). Instead wait until the spider-slayer(s) are within "web-distance" and just hold down the "Y" button. This action would typically wrap up a common bad guy, but it quickly destroys the spider-slayers!
(LATER MENTIONED)
Plus the "Impact Web" uses WAY too much webbing anyway!
More tricks, tips and cheats for this game are right here - Spiderman The Movie cheats