this is a start..
set display mode 800,600,32
`set manual refresh
sync on : hide mouse
`set right hand player's starting position
x1=750 : y1=300
`set left hand player's starting position
x2=50 : y2=300
do
`clear the screen - so old boxes are deleted
cls
`move right hand player up
if upkey() then dec y1,3
`move right hand player down
if downkey() then inc y1,3
`set right hand player's boundaries
if y1<55 then y1=55
if y1>545 then y1=545
`replace right hand player
box x1-20,y1-50,x1+20,y1+50
`use w and s to control player 2
if inkey$()="w" or inkey$()="W" then dec y2,3
if inkey$()="s" or inkey$()="S" then inc y2,3
if y2<55 then y2=55
if y2>545 then y2=545
box x2-20,y2-50,x2+20,y2+50
`refresh the screen
sync
loop
probably easier to use sprites though...
life's one big game