This is quite a tricky one to review...
Good points:
The animation was very smooth, the action most of the time was pulled off very well, it had some fairly original parts (giant Mario for instance)
Bad points:
The action sequence was very broken and...it's hard to explain. It sort of started, got into a really smooth flow then aprubtly stopped and the music suddenly changes from this fighting style music to relaxing mario music in the blink of an eye.
Also, alot of things didn't make sense. Such as why Mario suddenly 'evolved' when he was in a pipe, why Mario kept calling Luigi's name after beating him up (not a big issue), and why they were fighting in the first place.
The ending was just completely unsatisfying
Overall it was fairly entertaining and enjoyable, just a few little things and the structure of the film that let it down =]
On a completely different note: The only similarities I see with this to SMBZ is that. 1) There is fighting and 2) Mario sprites were used...
The fighting style is completely different and way more exaggetated in SMBZ! Sheesh...