How the mechanics/aiming feel compared to Unit 13? Sorry I would download the demo but I don't have space on my card.
IIRC, Unit 13 has some aimbot in it. Resistance has none at all. It's up to you to aim and fire, so no quick-scoping etc. I like that aspect. If you've liked the previous Resistance games, this one won't disappoint.
Honestly, some of these reviewers praise iOS FPS games and I guarantee this plays better than any of those. I've read several reviews asking "what's new here/same old thing". They seem to be ignorant of the fact that they are playing a fully capable FPS on a PORTABLE SYSTEM WITH 2 THUMB STICKS
. It's never been done before reviewers. That's what's new! Get a clue.