I got the game yesterday. Finished it today with a play time of 3h 41m, completing and getting everything. There were a few tricky spots, but all in all, it wasn't terribly hard. Then again, I was a Megaman freak back in the day, so I was already used to these type of challenges. For those that aren't, expect a challenge.
Even though this was meant to be reminiscent to the days of retro, I do wish there was more to it, both in design and content. $6-7 would have been a good price for this, as I feel $9 is a bit too much.