Doubly linked list in C: solved exercise with insert and traversal

#include <stdio.h>
#include <stdlib.h>

typedef struct Node {
    int value;
    struct Node *next;
    struct Node *prev;
} Node;

Node *append(Node *head, int value) {
    Node *newNode = (Node *)malloc(sizeof(Node));
    if (newNode == NULL) {
        fprintf(stderr, "Memory allocation error.\n");
        return head;
    }

    newNode->value = value;
    newNode->next = NULL;
    newNode->prev = NULL;

    if (head == NULL) {
        return newNode;
    }

    Node *current = head;
    while (current->next != NULL) {
        current = current->next;
    }

    current->next = newNode;
    newNode->prev = current;
    return head;
}

Node *getTail(Node *head) {
    if (head == NULL) {
        return NULL;
    }

    while (head->next != NULL) {
        head = head->next;
    }

    return head;
}

void traverseForward(Node *head) {
    printf("Forward traversal:\n");
    while (head != NULL) {
        printf("%d ", head->value);
        head = head->next;
    }
    printf("\n");
}

void traverseBackward(Node *tail) {
    printf("Backward traversal:\n");
    while (tail != NULL) {
        printf("%d ", tail->value);
        tail = tail->prev;
    }
    printf("\n");
}

void freeList(Node *head) {
    while (head != NULL) {
        Node *tmp = head;
        head = head->next;
        free(tmp);
    }
}

int main(void) {
    Node *list = NULL;

    list = append(list, 10);
    list = append(list, 20);
    list = append(list, 30);

    traverseForward(list);
    traverseBackward(getTail(list));

    freeList(list);
    return 0;
}

Forward traversal:
10 20 30
Backward traversal:
30 20 10