It's Tobey Maguire who makes "Spider-Man," PEOPLE movie critic Leah Rozen writes in the latest issue about the comic-book hero's new screen adventure. "A charmingly bemused performance," Rozen says about Maguire, "whose essential passivity works to his advantage here." She also likes the chemistry between Maguire and costar Kirsten Dunst, 20. Still, the 26-year-old actor, whose credits included "The Cider House Rules," "The Ice Storm" and "Wonder Boys," did seem an unlikely candidate for the role of the dashing wall crawler. In fact, Ewan McGregor and Leonardo DiCaprio were both reportedly up for the part. Yet Maguire says he was undaunted. "Hearing people question my casting helped motivate me," he told the New York Post. "I trained for five months, six days a week -- anywhere from an hour and a half to four hours a day doing a combination of gymnastics, yoga, martial arts, weight training and high-end cardio. My nutritionist said I was more committed than most professional athletes." Once in shape, it was time to don the costume, which also presented challenges. "They'd have to sew me into the suit because the zippers would break all the time," Maguire told the Associated Press. "And that would make me a little uneasy because I would be, like, harnessed up on a wire. Sometimes I would get a little thirsty and it'd be like, all right it's going to be 20-25 minutes before I can get a drink, at best." Even worse, he admitted, was when he had to go to the bathroom: "That'd be a little bit of a process."