I wouldn't dismiss the whole thing as utter garbage, nor the fact that they use Meat's voice singing (the likelihood of finding an actor who resembled Meat well enough and could even approximate his singing is pretty remote). I think the actors did a fair job, but it is very flawed in terms of accuracy.
Meat has packed such a lot into his career, no film lasting an hour and a quarter could cover it well. It would need the made for TV two parter to even attempt to do it justice. A large chunk of the film is devoted to the attempts to get Bat out of Hell released and the immediate aftermath, to the exclusion of so much more .. but what is inexcusable are the inaccuracies which imo were simply not required to bring the film in within the time constraints, eg how and when he met his first wife, the birth of his daughter Amanda, how he came to get the signature red scarf. Given they based it on his autobiography, there seems no excuse to get so many significant things wrong.
At the time of its first screening we were told that Meat, who had been very happy when he first met W Earl Brown (I didn't realise he came from Maine btw
) hated the final version .. and I can understand why.
I watched it when I was first able to, have watched it since .. but always with the knowledge that it falls very short of doing Meat justice.