Python game with error

# simple example of a hangman game by victor gatto
import time
counter = 0
letter = raw_input('Enter a word: ')
letterlist = []
hangman = []
lsf = ''
for eachcharacter in letter:
  letterlist.append(eachcharacter)
print letterlist
letterlen = len(letter)
letterguess = []
while counter < letterlen:
  letterguess.append('_')
  counter+=1
print letterguess
while not '!' in hangman:
  word = raw_input('Enter a letter: ')
  if word in letterlist:
    enum = [i for i,x in enumerate(letterlist) if x == word]
    bracketstrip = (str(w) for w in enum)
    z = int(''.join(bracketstrip))
    letterguess[z] = word
    ## letterguess[z] = word here only gets one letter! if they guess a letter
    ## that appears twice in the word, it should add both letters into
    ## their respective positions, but instead it throws an idex error!
    print letterguess

  else:
    if not 'h' in hangman:
      print 'Uh oh, that letter wasn\'t in the word! you get a H!'
      hangman.append('h')
      time.sleep(5)
      os.system('cls')
    elif not 'a' in hangman:
      print 'Uh oh, that letter wasn\'t in the word! you get a A!'
      hangman.append('a')
      time.sleep(5)
      os.system('cls')
    elif not 'n' in hangman:
      print 'Uh oh, that letter wasn\'t in the word! you get a N!'
      hangman.append('n')
      time.sleep(5)
      os.system('cls')
    elif not 'g' in hangman:
      print 'Uh oh, that letter wasn\'t in the word! you get a G!'
      hangman.append('g')
      time.sleep(5)
      os.system('cls')
    elif not 'm' in hangman:
      print 'Uh oh, that letter wasn\'t in the word! you get a M!'
      hangman.append('m')
      hangman.append(' ')
      time.sleep(5)
      os.system('cls')
    elif not 'a' in hangman[5]:
      print 'Uh oh, that letter wasn\'t in the word! you get a A!'
      hangman[5] = 'a'
      time.sleep(5)
      os.system('cls')
    else:
      print 'Uh oh, that letter wasn\'t in the word! you get a N!'
      hangman.append('n')
      hangman.append('!')
      time.sleep(5)
      os.system('cls')
      if hangman[0] == 'h' and hangman[1] == 'a' and hangman[2] == 'n' and hangman[3] == 'g' and hangman[4] == 'm' and hangman[5] == 'a' and hangman[6] == 'n':
        print 'Sorry mate, you just hangman... Game Over!'
        time.sleep(5)
        sys.exit()