Codes:

 Level codes:

 2 -  AAJIHGDDC    3 - CGGHDGGDG    4 - HDICICCII
 5 -  IDHEHDGCC    6 - IJIIDIHEC    7 - CFDFEFEFJ
 8 -  JIIJIIIIC    9 - AAAABAAAA   10 - CCGDGBBBB
 11 - HHIAAAJJIG  12 - GGDDJJHFD   13 - JIECBFGFF
 14 - HGGEDDCCB   15 - HHHGFGDCC   16 - 20 IHHDCHGHFF

 Holo codes:

 BODY  GRAB  BMHD  CMAP  DLTA

 If you type ALIENSAREFAGGOTS at the computer terminal on the 2nd
 level you will get immortal!