Downloaded the episode from <a href='http://www.megaupload.com/?d=yffagim0' target='_blank' rel='nofollow'>MU</a> and gave it a watch. Thoughts:
I sorta like the opening, it's a remix of the original, not the best remix (it's got nothing on Masaaki Endoh), but not bad.
I didn't like how we're thrown in the middle of the action either. I don't mind there being some rangers active by the start of it, but it's kind of nice to be introduced to things along with the protagonist(s). The episode also felt more like a character piece for the green ranger. Which hey, is great and all, but those usually pop up after 3-5 episodes, right? So we can get familiar with -all- the characters a bit before you give them focused development? As it is, the characters are mostly dull outside of the green ranger...who isn't very impressive himself.
The puns from the monster made me groan, and I usually -like- puns.
I didn't mind the Skull replacement. It felt nostalgic, so I'd say so far they've done a decent job of capturing the Bulk/Skull dynamic, even if Bulk did most of the work for that.
Also, replace the word 'samurai' every time it's said with 'ninja' and the feel of the episode would be more appropriate.
While not the worst start to the show, as I do think there's been worse episodes, I only recently watched RPM for the first time, and that show was great, for all that it heavily ripped off storytelling elements from In Space. This just felt mediocre by far.