I won't re-code the whole game for you but i'll point you in the right direction.
First your do loop is way too big. You need to use functions to split up all the code to small functions. If you need help with functions heres a link to a message talking about them.
http://forum.thegamecreators.com/?m=forum_view&t=57265&b=10
Second you can achieve the same results by putting the x coordinates of each bad guy sprite in a dim statement. Instead of having: j jj jjj jjjj jjjjj jjjjjj You can take it all down to:
When things are dimed like that you can easily switch with a simple for next loop:
a=0
for t=0 to 6
j(t)=a
inc a,50
next t
So it's easy to move all sprites with one for next loop rather than 15 lines of basically the same code.
Try some things out and if you get stuck post the code you've got so far and i'll try to help you more.