diff --git a/src/Level.hs b/src/Level.hs
index 6fcff1faa..03129d3e4 100644
--- a/src/Level.hs
+++ b/src/Level.hs
@@ -29,7 +29,7 @@ data LevelName = LambdaCave Int | Exit
 -- the strength of the character and the strength of the monsters present
 -- could further influence the chance, and the chance could also affect
 -- which monster is generated.
-monsterGenChance :: LevelName -> [Monster] -> Rnd Bool
+monsterGenChance :: LevelName -> [Movable] -> Rnd Bool
 monsterGenChance (LambdaCave n) ms =
   chance $ 1%(fromIntegral (250 + 200 * (L.length ms - n)) `max` 50)
 monsterGenChance _ _ = return False
diff --git a/src/Monster.hs b/src/Monster.hs
index 591256a63..88becf6b7 100644
--- a/src/Monster.hs
+++ b/src/Monster.hs
@@ -19,15 +19,10 @@ heroHP config =
   in  k + b `div` (k + 1)
 
 -- | Initial hero.
-defaultHero :: Char -> String -> Loc -> Int -> Hero
+defaultHero :: Char -> String -> Loc -> Int -> Movable
 defaultHero symbol name ploc hp =
   Movable (Hero symbol name) hp hp Nothing TCursor ploc [] 'a' 10 0
 
--- The types should be equal, becase monsters can be sometimes
--- player-controlled and heroes can be alien-controlled or panicked, etc.
-type Hero = Movable
-type Monster = Movable
-
 data Movable = Movable
                 { mtype   :: !MovableType,
                   mhpmax  :: !Int,
@@ -120,7 +115,7 @@ monsterFrequency =
   ]
 
 -- | Generate monster.
-newMonster :: Loc -> Frequency MovableType -> Rnd Monster
+newMonster :: Loc -> Frequency MovableType -> Rnd Movable
 newMonster loc ftp =
     do
       tp <- frequency ftp
diff --git a/src/State.hs b/src/State.hs
index dfa382665..276776393 100644
--- a/src/State.hs
+++ b/src/State.hs
@@ -121,10 +121,10 @@ insertActor a m =
     AHero n    -> updateLevel (updateHeroes   (IM.insert n m))
     AMonster n -> updateLevel (updateMonsters (IM.insert n m))
 
-levelHeroList :: State -> [Hero]
+levelHeroList :: State -> [Movable]
 levelHeroList (State { slevel = Level { lheroes = hs } }) = IM.elems hs
 
-levelMonsterList :: State -> [Monster]
+levelMonsterList :: State -> [Movable]
 levelMonsterList (State { slevel = Level { lmonsters = ms } }) = IM.elems ms
 
 updateCursor :: (Cursor -> Cursor) -> State -> State