Really rough around the edge way (not complete) way to grab all product attributes to a csv with direct SQL in Magento. Don't trust this worth your life :)

export-all-product-attributes.php

<?php
/**
 * export-all-product-attributes.php
 * @author      Tegan Snyder <tsnyder@tegdesign.com>
 */

// init Magento
require_once('app/Mage.php');
umask(0);
Mage::app('default');

// setup database connection
$db_conn = Mage::getSingleton('core/resource');
$r_conn = $db_conn->getConnection('core_read');

// grab all attribute_codes
$sql = "SELECT DISTINCT attribute_code FROM eav_attribute WHERE entity_type_id IN (SELECT entity_type_id FROM eav_entity_type WHERE entity_type_code = 'catalog_product')";
$results = $r_conn->fetchAll($sql);
$attribute_codes = array();
foreach ($results as $row) {
	$attribute_codes[$row['attribute_code']] = '';
}

$attribute_codes = array_keys($attribute_codes);

// grab a list of your skus that are SIMPLE products... 
$sql = "SELECT sku FROM catalog_product_entity WHERE type_id = 'simple'";
$results = $r_conn->fetchAll($sql);

// limit the products to a specific store
$store_id = 0;

// counter for header
$x = 0;
$y = 0;

foreach ($results as $row) {

	// grab product attributes for sku into array
	$product_attributes = array();
	$product_attributes = getAttributes($store_id, $row['sku'], $attribute_codes);

	if (isset($product_attributes['skipped'])) {
		continue;
	}

	// loop through attributes array
	foreach ($product_attributes as $k => $n) {

		// print headers
		if ($x == 0) {
			echo '"sku","' . implode('","', array_keys($n)) . '"' . PHP_EOL;
		}

		if (count(array_filter($n)) == 0) {
			continue;
		}

		// output in comma enclosed csv format
		echo '"' . $row['sku'] . '","' . implode('","', $n) . '"' . PHP_EOL;

		// increment counter
		$x = $x + 1;

	}

	$y = $y + 1;

}

/**
 * Get product attributes via direct SQL
 */

function getAttributes($store_id, $sku, $attribute_codes) {

	global $db_conn, $r_conn;

$sql = <<<"SQL"
	SELECT * FROM ( SELECT
	    ce.sku,
	    ea.attribute_id,
	    ea.attribute_code,
	    CASE ea.backend_type
	       WHEN 'varchar' THEN ce_varchar.value
	       WHEN 'int' THEN ce_int.value
	       WHEN 'text' THEN ce_text.value
	       WHEN 'decimal' THEN ce_decimal.value
	       WHEN 'datetime' THEN ce_datetime.value
	       ELSE ea.backend_type
	    END AS value,
	    CASE ea.backend_type
	       WHEN 'varchar' THEN ce_varchar.store_id
	       WHEN 'int' THEN ce_int.store_id
	       WHEN 'text' THEN ce_text.store_id
	       WHEN 'decimal' THEN ce_decimal.store_id
	       WHEN 'datetime' THEN ce_datetime.store_id
	       ELSE ea.backend_type
	    END AS store_id,
	    ea.is_required AS required
	FROM catalog_product_entity AS ce
	LEFT JOIN eav_attribute AS ea 
	    ON ce.entity_type_id = ea.entity_type_id
	LEFT JOIN catalog_product_entity_varchar AS ce_varchar 
	    ON ce.entity_id = ce_varchar.entity_id 
	    AND ea.attribute_id = ce_varchar.attribute_id 
	    AND ea.backend_type = 'varchar'
	LEFT JOIN catalog_product_entity_int AS ce_int 
	    ON ce.entity_id = ce_int.entity_id 
	    AND ea.attribute_id = ce_int.attribute_id 
	    AND ea.backend_type = 'int'
	LEFT JOIN catalog_product_entity_text AS ce_text 
	    ON ce.entity_id = ce_text.entity_id 
	    AND ea.attribute_id = ce_text.attribute_id 
	    AND ea.backend_type = 'text'
	LEFT JOIN catalog_product_entity_decimal AS ce_decimal 
	    ON ce.entity_id = ce_decimal.entity_id 
	    AND ea.attribute_id = ce_decimal.attribute_id 
	    AND ea.backend_type = 'decimal'
	LEFT JOIN catalog_product_entity_datetime AS ce_datetime 
	    ON ce.entity_id = ce_datetime.entity_id 
	    AND ea.attribute_id = ce_datetime.attribute_id 
	    AND ea.backend_type = 'datetime'
	WHERE ce.sku = "$sku") AS tab WHERE tab.value != ""
SQL;

	$results = $r_conn->fetchAll($sql);

	$product_attributes = array();

	foreach ($results as $row) {

		if ($row['store_id'] != $store_id) {

			$product_attributes['skipped'] = true;

			return $product_attributes;
		}

		foreach ($attribute_codes as $attr_code) {

			if (!isset($product_attributes[$row['store_id']][$attr_code])) {

				$product_attributes[$row['store_id']][$attr_code] = '';

			}

		}

		if ($row['value'] == 'static') {

				if ($row['attribute_code'] == 'category_ids') {

					$sql = 'SELECT entity_id FROM catalog_product_entity WHERE sku = "' . $sku . '"';
					$a_val = $r_conn->fetchAll($sql);

					if (isset($a_val[0]['entity_id'])) {

						$sql = 'SELECT GROUP_CONCAT(category_id) as category_ids FROM catalog_category_product WHERE product_id = ' . $a_val[0]['entity_id'];
						$c_val = $r_conn->fetchAll($sql);

						$product_attributes[$store_id][$row['attribute_code']] = $c_val[0]['category_ids'];

					}

				} else {

					$sql = 'SELECT entity_id, ' . $row['attribute_code'] . ' FROM catalog_product_entity WHERE sku = "' . $sku . '"';
					$a_val = $r_conn->fetchAll($sql);

					if (isset($a_val[0][$row['attribute_code']])) {

						$product_attributes[$store_id][$row['attribute_code']] = $a_val[0][$row['attribute_code']];

					}

				}

		} else {
			
			$product_attributes[$row['store_id']][$row['attribute_code']] = $row['value'];

		}

	}

	return $product_attributes;

}

run like this:

php export-all-product-attributes.php > output-file.csv