Como da "zoom" no jogo ?

Estou desenvolvendo um jogo de guerra e plataforma, mas quando compilo o programa o personagem e o cenário ficam muito pequenos, então eu gostaria de saber com que deixar o cenário e o personagem mais "perto" tipo super mario bros do nintendinho.

#include <allegro5\allegro.h>
#include <allegro5\allegro_native_dialog.h>
#include <allegro5\allegro_image.h>

const float FPS = 60;
const int SCREEN_W = 850;
const int SCREEN_H = 640;
const int BLUE = 64;

enum TECLADO { KEY_UP, KEY_DOWN, KEY_LEFT, KEY_RIGHT };

int main()
{
//_______VARIAVEIS DO JOGO________

ALLEGRO_DISPLAY *display = NULL;
ALLEGRO_BITMAP *Blue = NULL;
ALLEGRO_BITMAP *Cenario = NULL;
ALLEGRO_EVENT_QUEUE *event_queue = NULL;
ALLEGRO_TIMER *timer = NULL;

float bouncer_x = SCREEN_W / 2.0 - BLUE / 2.0;
float bouncer_y = SCREEN_H / 2.0 - BLUE / 2.0;
bool key[4] = { false, false, false, false };
bool redraw = true;
bool doexit = false;

//________INICIALIZAÇÃO DO ALLEGRO 5__________
if (!al_init()) {
al_show_native_message_box(display, "Error", "Error", "Failed to initialize allegro!",

NULL, ALLEGRO_MESSAGEBOX_ERROR);
return 0;
}

if (!al_init_image_addon()) {
al_show_native_message_box(display, "Error", "Error", "Failed to initialize al_init_image_addon!",

NULL, ALLEGRO_MESSAGEBOX_ERROR);
return 0;
}

//al_set_new_display_flags(ALLEGRO_FULLSCREEN);
display = al_create_display(800, 600);

if (!display) {

al_show_native_message_box(display, "Error", "Error", "Failed to initialize display!",

NULL, ALLEGRO_MESSAGEBOX_ERROR);
return 0;
}

Blue = al_load_bitmap("Blue.bmp");

if (!Blue) {

al_show_native_message_box(display, "Error", "Error", "Failed to load image!",

NULL, ALLEGRO_MESSAGEBOX_ERROR);
al_destroy_display(display);
return 0;
}

Cenario = al_load_bitmap("Cubo.bmp");

if (!Cenario) {

al_show_native_message_box(display, "Error", "Error", "Failed to load image!",

NULL, ALLEGRO_MESSAGEBOX_ERROR);
al_destroy_display(display);
return 0;
}

event_queue = al_create_event_queue();

if (!event_queue) {

al_show_native_message_box(display, "Error", "Error", "Failed to create event_queue!",

NULL, ALLEGRO_MESSAGEBOX_ERROR);
al_destroy_display(display);
return 0;
}

timer = al_create_timer(3.0 / FPS);

if (!timer) {

al_show_native_message_box(display, "Error", "Error", "failed to create timer!",

NULL, ALLEGRO_MESSAGEBOX_ERROR);
al_destroy_display(display);
return 0;
}

al_set_target_bitmap(al_get_backbuffer(display));

//______INSTALAÇÃO________
al_install_keyboard();

//________REGISTRO___________

al_register_event_source(event_queue, al_get_display_event_source(display));

al_register_event_source(event_queue, al_get_timer_event_source(timer));

al_register_event_source(event_queue, al_get_keyboard_event_source());

al_flip_display();

al_start_timer(timer);

//_________LOOP PRINCIPAL__________

while (!doexit)
{

ALLEGRO_EVENT ev;
al_wait_for_event(event_queue, &ev);

if (ev.type == ALLEGRO_EVENT_TIMER) {
if (key[KEY_UP] && bouncer_y >= 4.0) {
bouncer_y -= 4.0;
}

if (key[KEY_DOWN] && bouncer_y <= SCREEN_H - BLUE - 4.0) {
bouncer_y += 4.0;
}

if (key[KEY_LEFT] && bouncer_x >= 4.0) {
bouncer_x -= 4.0;
}

if (key[KEY_RIGHT] && bouncer_x <= SCREEN_W - BLUE - 4.0) {
bouncer_x += 4.0;
}

redraw = true;
}
else if (ev.type == ALLEGRO_EVENT_DISPLAY_CLOSE) {
break;
}
else if (ev.type == ALLEGRO_EVENT_KEY_DOWN) {

switch (ev.keyboard.keycode) {
case ALLEGRO_KEY_W:

key[KEY_UP] = true;
break;

case ALLEGRO_KEY_S:

key[KEY_DOWN] = true;
break;

case ALLEGRO_KEY_A:

key[KEY_LEFT] = true;
break;

case ALLEGRO_KEY_D:

key[KEY_RIGHT] = true;
break;
}
}
else if (ev.type == ALLEGRO_EVENT_KEY_UP) {

switch (ev.keyboard.keycode) {
case ALLEGRO_KEY_W:

key[KEY_UP] = false;
break;

case ALLEGRO_KEY_S:

key[KEY_DOWN] = false;
break;

case ALLEGRO_KEY_A:

key[KEY_LEFT] = false;
break;

case ALLEGRO_KEY_D:

key[KEY_RIGHT] = false;
break;

case ALLEGRO_KEY_ESCAPE:

doexit = true;
break;
}
}

if (redraw && al_is_event_queue_empty(event_queue)) {

redraw = false;

al_clear_to_color(al_map_rgb(255, 255, 255));

al_draw_bitmap(Cenario, 0, 0, 0);

al_draw_bitmap(Blue, bouncer_x, bouncer_y, 0);

al_flip_display();
}
}

while (1);

//________DESTRUIR_________

al_destroy_display(display);
al_destroy_bitmap(Blue);
al_destroy_bitmap(Cenario);
al_destroy_event_queue(event_queue);
al_destroy_timer(timer);

return 0;
}