Simple, straightforward, bloody good fun from start to finish, and a pretty good way to cap off the Cyber Hell series.
Damian's small hitbox is a pretty major double-edged sword - whilst it makes dodging bullets relatively straightforward, it makes absorbing them a lot iffier. This is especially apparent against that bat and its spray of seriously small squares.
Absorbing red bullets is also tougher than it should, given they blend in with Red Damian's suit.
Personally, hard mode felt easier than regular to me - sure, you lose access to the Ikaruga-style bullet absorption and its associated beam attack, but you also completely sidestep that mechanic's more awkward parts.
Cyberdevil did a pretty good job putting a face to the Cyber Devil.