Qix Cheats (PC)

For infinite lives in this game, use the DOS utility DEBUG. First backup the
  game to be edited, then type the following from the DOS prompt:

  ren main.dat cheater.cht
  debug
  a 100
  mov dx,es
  add dx,1000
  mov es,dx <PRESS ENTER TWICE>

  g 108
  r ip 100
  ncheater.cht
  l
  e es:11aa 0
  e es:11d1 0
  Then type: w
  q

  Then rename CHEATER.CHT back to its previous name.