the way you zoom a camera is by adjusting lens width or fov(field of view) i coudn't get your game to work(for some reason some of the media didn't load right)

                                    ` This code was downloaded from The Game Creators
                                    ` It is reproduced here with full permission
                                    ` http://www.thegamecreators.com
                                    
                                    Rem Project: Zoooom
Rem Created: 3/26/2006 6:09:40 PM

Rem ***** Main Source File *****

rem zoooom in with the mouse.

SET DISPLAY MODE 1280,1024,0
set window size 128*5,102*5
MAKE OBJECT SPHERE 1,20,20,20
POSITION OBJECT 1,0,0,50
MAKE OBJECT SPHERE 2,20,20,20
POSITION OBJECT 2,0,0,0
MAKE OBJECT SPHERE 3,20,20,20
POSITION OBJECT 3,100,0,-50


AUTOCAM OFF
MAKE CAMERA 1
POSITION CAMERA 1,200,0,0
YROTATE CAMERA 1,270



DO
fov = mousey()/10
if fov > 100 then fov = 100
if fov< 1 then fov = 1
set camera fov 1,fov
LOOP