starman.hs

-- check   "hola"    "---a"    'b'  =  (False, "---a")
check   :: String -> String -> Char -> (Bool,String)
check word display c =
  (c `elem` word, [if x == c
                   then c
                   else y | (x, y) <- zip word display])

mkguess :: String -> String -> Int -> IO ()
mkguess word display n =
  do putStrLn (display ++ "  " ++ take n (repeat '*'))
     if n == 0 then putStrLn ("You lose.  " ++ word)
               else do
                 putStr "  Enter your guess: "
                 q <- getLine
                 let (correct, display') = check word display (q!!0)
                 let n'                  = if correct then n else n-1
                 if word == display' then putStrLn "You win!"
                                     else mkguess word display' n'

starman :: String -> Int -> IO ()
starman word n = mkguess word ['-' | _ <- word] n

All the hard work is done by 'check', so it's important to keep it pure (no IO). The interactive part is done by 'mkguess', so it must be impure. And finally it is good to have an initialization function, for example to read a data file at the start of the program (also impure) ' starman' is a good place. And that's all. Only two impure functions.
Look at the signature of 'turn' and 'mkguess'. It's the same. It's easy to combine them!
See: https://www.futurelearn.com/courses/functional-programming-haskell/1/steps/116475/comments#fl-comments