Good movie, really annoying when thought about

Rating: 5/10 (21 June 2014)

It's a good movie, it was enjoyable and well animated, if it was a stand alone film (as in Shrek didn't exist) then it would be even better. But that is why I only gave it a 5 because it has one of the biggest plot holes I have ever seen in a film.
The premise of the movie is that Puss was wrongfully labelled a criminal and then became an outlaw, and he spends the movie trying to right his wrongs and let everybody know that he is a nice, law abiding cat. So if this is all a prelude to Shrek, and Puss really is a nice guy and doesn't want to break the law and tries so hard to prove his innocence, why does he then become a hit-man? A sellsword if you will?
In Shrek 2, The King hires Puss to kill Shrek, as Puss is the only one who could manage the job. This means that he has been in the industry for quite a while. Meaning that he isn't actually a law abiding cat. This is why I didn't end up liking Puss in Boots.
It was a good film, and as an independent film it would be marvellous, but I just cannot look past this problem, it's like the creators either didn't care enough about their movies to realise this problem, or knew about it but just couldn't care enough to bother changing it.