Have more fun with your comments and exercise a wider imagination. “Fuck” is so passé, forgettable. Here are some examples one can start with instead:
“Foul”, “abominable”, “inelegant”, “pig disgusting”, “Lovecraftian horror”, “poor imitation of a program”, “Beelzebub himself hath not seen such filth”, “fatally bad”, “eye poison”, “something an uphill ant with asthma would outperform”, “in need of various religious rites performed thereof before it can be deleted and erased from history”, “the monkey that thought he could”, “most unclean”, “Satanic verses”, “dark incantations”, “PHP-esque”, “unimaginably without precedent”, “platonic primordial soup”, “insidious”, “binders full of bad lines of code”, “darkness”, “interdimensional miscalculation”, “code of the beast”, “something wicked this way compiles”, “unimportable”, “it keeps asking me if I'm the keymaster”, “someone crossed the streams and this is what resulted”, “illegitimate spawn”, “algorithmically destitute”, “abandoned depravity”, “Brendlefly”, “ocean of slime”, “The Da Vinci Couldn't”, etc.
That's if you think the code is OK. If you think the code is great:
“Not bad”, “can't see any problems so far”, “suspiciously unbroken.”