Rating:

* extract files by using binwalk

```
$ binwalk -D 'png image:png' GottaGoDeeper.png

(snip)

$ ls _GottaGoDeeper.png.extracted/
0.png 14B123 150E4A 7E50B.png 7E5A4.zlib 88CDF7 8C 8C.zlib
14B0CE.png 14B123.zlib 150E4A.zlib 7E5A4 88CD5E.png 88CDF7.zlib 8C812D.png
```

* analyse 14B0CE.png by using 青い空を見上げればいつもそこに白い猫 (https://digitaltravesia.jp/usamimihurricane/webhelp/_RESOURCE/MenuItem/another/anotherAoZoraSiroNeko.html)

I got a string "ZXJXZU".

```text
7E50B.png => TWICE RnlaWDA9
8C812D.png => ZmxhZ
14B0CE.png => ZXJXZU
88CD5E.png => tEZWVw
```

* I got a flag by running following python code

```python
#!/usr/bin/env python3
# coding: utf-8

from base64 import b64decode
from itertools import permutations

T = []
for i in range(26):
T += [chr(ord('A') + i)]
T += [chr(ord('a') + i)]
for i in "0123456789+/":
T += [i]

L = ["RnlaWDA9", "ZmxhZ", "ZXJXZU", "tEZWVw"]

for t in T:
for i in list(permutations(L[1:] + [t])):
i = list(i)
i += [b64decode(L[0]).decode("utf-8")]
s = "".join(i)

try:
ret = b64decode(s)
if not "\\x" in str(ret) and "flag" in str(ret):
print (ret.decode("utf-8"))
except:
print ("Error")
```

* Execution result

```
flag+DeeperWeAre}
erWeKDeepflag!re}
flag;DeeperWeAre}
erWeKDeepflag1re}
flagKDeeperWeAre}
erWeKDeepflagAre}
flag[DeeperWeAre}
erWeKDeepflagQre}
flagkDeeperWeAre}
erWeKDeepflagare}
flag{DeeperWeAre}
erWeKDeepflagqre}
```

flag: `flag{DeeperWeAre}`