I'm not very happy with how the Lizard turned out. Why was Connor's  lizard form a body builder? Too muscular, and just too big in general to  the point that it looks silly. Those gigantic hands busting through the  windows of the car in the bridge scene look terrible.
The face and the skin/scale detail are actually good, just not good  enough to have him standing fully in frame, naked in brightly lit areas.  The labcoat could've done so much to conceal the cgi and add to the  complexity of his appearance. 
Why didn't this happen?:
Aside from his appearance, I don't like how the Connors/Lizard  relationship was handled. Originally Connors turned himself into a  Lizard by mistake and remained that way until he was cured by  Spider-man, at which point he returns to his 'good' human persona. 
By making Connors repeatedly and intentionally turn himself into the  Lizard during the movie, aswell as creating his evil plan while in human  form, you make Connors evil rather than just the Lizard. So why does  Connors suddenly turn 'good' at the end of the movie after he returns to  human form, when he had already returned to human form multiple times? I  guess the antidote made his mind revert back to the time before the  first injection or something...
Also, why exactly did he chase after Dr Ratha when he transforms the first time?
Rather than make the 'Lizard serum' effects temporary, I think I  would've preferred if he transformed once, made his master plan then  gets cured. It would've created a much more defined barrier between the  two personas, and allowed us (aswell as Spider-man) to sympathize more  with Connors and his family. Then it would've been acceptable for  Spider-man to let Connors go free, which I think would be better.
On the plus side I was happy with the master plan, as well as the scenes  with actual lizards crawling around. I saw this as a nice reference to  the comic Lizard's ability to manipulate reptiles.