I read the thread on shmups forum for this-- apparently yes, there are a few bugs, but the folks who actually did the porting for this are members there and are taking the issues into account, so I don't doubt that they will be fixed in due time. Should have had a demo or something to catch the issues early, but I suppose.
After playing a bit more I do notice some framerate drop and stuttering, especially when playing fullscreen-- but I'm sure a lot of that is my laptop and with the mass amounts of whining on shmups forum, I hope is their first issue to fix.
Still way, way, way better than the PS2 port.