Dungeon Game Feedback

import random
import os

cells = [] # list of tuples that represent the board
player = {"old": []} # player will contain "current" and list of old locations
board = [] # for drawing the board

def make_board(size):
    new_board = []
    for i in range(0, size * 4):
        if i % 4 == 0:
            new_board.append(" ___ " * size)
        elif i % 4 == 3:
            new_board.append("|___|" * size)
        else:
            new_board.append("|   |" * size)
    return new_board

def get_locations():
    monster = random.choice(cells)
    door = random.choice(cells)
    player = random.choice(cells)

    # if monster, door, or start are the same, do it again
    if monster == door or monster == player or player == door:
        return get_locations()

    return monster, door, player

def move_player(player, move):
    x, y = player["current"] # can't modify player itself since it's a tuple
    player["old"].append((x, y))

    if move == "LEFT":
        y -= 1
    elif move == "RIGHT":
        y += 1
    elif move == "UP":
        x -= 1
    elif move == "DOWN":
        x += 1

    return x, y

def get_moves(player, size):
    moves = ["LEFT", "RIGHT", "UP", "DOWN"]
    # player = (x, y)
    if player[0] == 0:
        moves.remove("UP")
    elif player[0] == size - 1:
        moves.remove("DOWN")
    if player[1] == 0:
        moves.remove("LEFT")
    elif player[1] == size - 1:
        moves.remove("RIGHT")
    return moves

def draw(player, size, show_unknown = False, unknown = None, unknown_letter = None):
    clear()

    board = make_board(size)
    tups = player["current"] 

    line = list(board[4 * player["current"][0] + 2])
    if player["current"][1] == 0:
        line[4 * player["current"][1] + 2] = "X"
    else:
        line[5 * player["current"][1] + 2] = "X"
    board[4 * player["current"][0] + 2] = "".join(line)

    for item in player["old"]:
        if not item == player["current"]:
            line = list(board[4 * item[0] + 2])
            if item[1] == 0:
                line[4 * item[1] + 2] = "."
            else:
                line[5 * item[1] + 2] = "."
            board[4 * item[0] + 2] = "".join(line)

    if show_unknown and unknown != None:
        line = list(board[4 * unknown[0] + 2])
        if unknown[1] == 0:
            line[4 * unknown[1] + 2] = unknown_letter
        else:
            line[5 * unknown[1] + 2] = unknown_letter
        board[4 * unknown[0] + 2] = "".join(line)

    for line in board:
        print(line)

def clear():
    if os.name == 'nt':
        os.system('cls')
    else:
        os.system('clear')

# Welcome screen:
clear()
print("\nWelcome to the dungeon!\n")

# Create dungeon:
size = 4
try:
    size = int(input("Enter size of dungeon (def. 4): "))
except:
    print("Default size 4.")

for i in range(0, size):
    for j in range(0, size):
        cells.append((i, j))

# Fill dungeon:
monster, door, player["current"] = get_locations()

# Game loop:
clear()
message = ""
while True:
    moves = get_moves(player["current"], size)
    draw(player, size)

    if message != "":
        print(message)
    print("You're currently in room {}.".format(player["current"]))

    print("You can move {}.".format(", ".join(moves)))
    print("Enter QUIT to quit.")

    move = input("> ")
    move = move.upper()

    if move == "QUIT":
        break

    # if it's a good move, change the player's position
    if move in moves:
        player["current"] = move_player(player, move)
        message = ""
    else:
        message = "** Walls are hard, stop walking into them! **"
        continue

    if player["current"] == door:
        draw(player, size, show_unknown = True, unknown = monster, unknown_letter = "G")
        print("You escaped!")
        break
    elif player["current"] == monster:
        draw(player, size, show_unknown = True, unknown = door, unknown_letter = "D")
        print("You were eaten by the grue!")
        break