Red Faction 1 I really enjoyed. It had some really cool ideas.
Red Faction 2, I think I'm the only guy who did actually play it! When you load up the game It's pretty obvious that it's a port from the Xbox; the controls, the texture quality, and the teen-friendly content.
The only things it maintained from the original RF were the Geo-Mod™ Engine, vehicles, and the whole "fight the power" revolution thing. The story is completely unrelated.
Although RF2 technically had better graphics (better models, better effects) and an updated version of Geo-Mod, RF1 still looks better mainly because of how lo-res the textures are in RF2. RF2 just looks dusty to me, with a little too much "brown" in the colour scheme. Overall, RF2 felt much less refined than the original, and more like a rushed "let's make some console money" project.