Hi @Permanence
Have you read the code exmaples for conditional logic / understand what an if statement in PHP is?
Your code should look more like this:
<?php while(the_repeater_field('content_block')): ?>
<div class="clearfix">
<?php if( get_sub_field('title') ): ?>
<h2><?php the_sub_field('title'); ?></h2>
<?php endif; ?>
<div class="img"><img src="<?php the_sub_field('image'); ?>"></div>
<div class="txt"><?php the_sub_field('content'); ?> </div>
</div>
<?php endwhile ?>
