SDL_Rect draw bug (main.cpp)

#include <SDL/SDL.h>
#include <SDL_image/SDL_image.h>

#include "Player.h"
#include "Bullet.h"

#define WIDTH   475
#define HEIGHT  625
#define FPS     60

SDL_Surface* loadImage(char* filename) {
    SDL_Surface* loadedImage = IMG_Load(filename);
    SDL_Surface* optimized = NULL;
    if(loadedImage) {
        optimized = SDL_DisplayFormat(loadedImage);
        SDL_FreeSurface(loadedImage);
    }
    return optimized;
}

int main(int argc, char* argv[]) {
    SDL_Init(SDL_INIT_EVERYTHING);

    SDL_Surface* screen = SDL_SetVideoMode(WIDTH, HEIGHT, 32, SDL_SWSURFACE);
    SDL_WM_SetCaption("Galaga Test", NULL);

    //init
    Player player((WIDTH-25)/2, HEIGHT-35);
    Bullet bill(player.getX(), player.getY(), 0, -8);

    bool running = true;
    while(running) {
        SDL_FillRect(screen, NULL, SDL_MapRGB(screen->format, 0, 0, 0));
        SDL_Event event;
        int start = SDL_GetTicks();
        while(SDL_PollEvent(&event)) {
            if(event.type == SDL_QUIT) {
                running = false;
            } else if(event.type == SDL_KEYDOWN) {
                int key = event.key.keysym.sym;

                if(key == SDLK_RIGHT || key == SDLK_d) {
                    player.setXVel(6);
                } else if(key == SDLK_LEFT || key == SDLK_a) {
                    player.setXVel(-6);
                }
            } else if(event.type == SDL_KEYUP) {
                int key = event.key.keysym.sym;

                if(key == SDLK_RIGHT || key == SDLK_d) {
                    player.setXVel(0);
                } else if(key == SDLK_LEFT || key == SDLK_a) {
                    player.setXVel(0);
                }
            }
        }

        //update
        player.update();
        bill.update();
        if(player.getX() < 0 || player.getX()+player.getWidth() > WIDTH) {
            player.setX(player.getX()-player.getXVel());
            player.setXVel(0);
        }

        //render
        bill.render(screen);
        player.render(screen);

        int end = SDL_GetTicks();
        int duration = end-start;
        if(duration > (1000/FPS)) {
            SDL_Delay(5);
        } else {
            SDL_Delay((1000/FPS)-duration);
        }
        SDL_Flip(screen);
    }

    SDL_Quit();
    return 0;
}