Get Comments: Direct link to specific comment + post title

Instead of $comment->post_ID use $comment->comment_post_ID. Your code will look like following:

<?php   $comments = get_comments('status=approve&number=5'); ?>
<ul id="recent_comments">
<?php foreach ($comments as $comment) { ?>
<li><p><strong><?php
        $title = get_the_title($comment->comment_post_ID);
        echo get_avatar( $comment, '45' );
echo strip_tags($comment->comment_author); ?></strong>&nbsp;commented on <a href="https://wordpress.stackexchange.com/questions/28690/<?php echo get_permalink($comment->comment_post_ID); ?>" rel="external nofollow" title="<?php echo $title; ?>"> <?php echo $title; ?></a>: <?php echo wp_html_excerpt( $comment->comment_content, 45 ); ?> (...)</p></li>
<?php }  ?>
</ul>

You were doing right about adding comment’s div id at the end of URL for creating individual comment links. You need to add #comment-<?php echo $comment->comment_ID; ?> at the end of post permalink.

Here is how the anchor tag should look like.

<a href="<?php echo get_permalink($comment->comment_post_ID); ?>#comment-<?php echo $comment->comment_ID; ?>" rel="external nofollow" title="<?php echo $title; ?>"> <?php echo $title; ?></a>