^Suckerpunch has a very weak plot and character development. In more ways than one, it can be seen as very MCP/fanservice film for boys (or a male-dominated market). Even the action in the film can be rather blasé (due to the overuse of clichés) and mindless.
However, going beyond that, one would find that this film still has its merits, albeit in very niche areas.
Some say it's a bit of a Japanophile graphic artist's/otaku's/film maker's dream film. Hence, the featuring of a quite impressive array of weaponry (from chokutos to katanas; submachine guns to heavy weaponry), very well-executed/elaborate imagery and special effects in the "fantasy" bits as well as generally very impressive technicalities in merging CGI with reality/camera-captured imagery.
If you are a special effects person, it is definitely worth a watch. However, if you are the sort that MUST have a plot or some form of character development, look elsewhere. This film will only appeal to a select few.