It's probably easier and more readable to make it a switch/case statement like so:
$highscore = $mysqli->query("SELECT id,name,clicks,ip,factory FROM highscore ORDER BY clicks DESC LIMIT 0,50 ");
$ipquery = $mysqli->query("SELECT id,name,clicks,ip,factory FROM highscore WHERE ip = '".$_SERVER['REMOTE_ADDR']."'");
$arrayIP = $ipquery->fetch_array();
$levelown = 1;
function ifElse() {
global $levelown;
global $arrayIP;
switch (true) {
case $arrayIP['click'] > 3000:
$levelown = floor(($arrayIP['click']/1000)+8);
break;
case $arrayIP['click']== 3000:
$levelown = 11;
break;
case $arrayIP['click'] >= 2000:
$levelown = 10;
break;
case $arrayIP['click'] >= 1500:
$levelown = 9;
break;
case $arrayIP['click'] >= 1000:
$levelown = 8;
break;
case $arrayIP['click'] >= 750:
$levelown = 7;
break;
case $arrayIP['click'] >= 500:
$levelown = 6;
break;
case $arrayIP['click'] >= 350:
$levelown = 5;
break;
case $arrayIP['click'] >= 200:
$levelown = 4;
break;
case $arrayIP['click'] >= 50:
$levelown = 3;
break;
case $arrayIP['click'] >= 0:
$levelown = 2;
break;
}
$levelown = "Level " . $levelown;
}