I would say no. 34 bytes is 256^32=7588550360256754183279148073529370729071901715047420004889892225542594864082845696 combinations, and even if you could easily narrow it down to only valid programs you would still need to simulate it, which is way slower than computing a hash.
34 bytes is equivalent to bruteforcing a 272-bit key. It's already physically impossible to do that for a 256-bit key even if you ignore everything other than incrementing the key counter itself:
Or, you could evaluate whether said program draws the crossed lines in an emulator. Might not take that much longer than calculating the hash...
That makes this kind of an interesting "Genetic Programming" challenge... The solution space is "only" 29 bytes long...
I don't think that would be this quick either.
Since the code might/will mess up zeropage and/or other dataareas in use by the C64 basic, you would have to wipe it to a known state for each test, which almost means "boot up the KERNAL and let it run complete INIT".
Not that even this have to take a long while on a 3GHz computer running full speed, but doing it 2^272 times ...
No - what I mean is that if someone is worried that their code will be derived from their published hash by someone doing a brute-force attack, they can prevent (or make much harder) this brute-force attack by having comments in their source code.
I'm assuming here that the hashed string is the source code rather than the machine code.