Just eyeballing it, the cuneiform looks like Old Persian, so not really appropriate for Gilgamesh & Enkidu to begin with. And Old Persian had a diagonal character to separate words, which I see just once here (and it's oriented the wrong way, though that's probably just a matter of the font used). So I tend to agree that it's gibberish.
Still, Old Persian is relatively easy to transcribe, so... Gilgamesh's second bubble (the shortest passage) reads 𐎲𐎺𐎥𐎼𐎿𐎭𐎹𐎼 ba-va-ga-ra-sa-da-ya-ra. Does this mean anything in any language? I'm guessing not, but anyone who wants to investigate further is welcome to do so.
The artist said that (in a self-reply on Twitter) aside from the German, the words don't have meaning. (Does the artist include the Japanese lines in that estimation? Curious...)
Uruk chatterYou guys are regressing back too much!!!