Never played the first so I can't comment on it
I'll say this about this demo. Game feels like shit. Controls feels bad. The framerate is dodgy. And it locked up/crashed on me in the demo when me and my online partner died.
I came to say the same thing. This game is messy as fuck. Not only did it constantly run poorly and really affected aiming and basic controls, there were random glitches throughout. Then during one sequence in the middle, all audio cuts out and we're left watching mouths move with no speech.
First game was a fun competent gears clone with more focus on co-op, not great or anything, and I'm sure this could be too if it didn't run like shit. There was a firefight where it seemed like there was a second delay on just aiming; not milliseconds that people measured Killzone and Halo with, it felt like I could count between the time I moved the analog stick and the game reacted. Oh, and the netcode is awful. Constantly it would be stop and say "waiting for other player" for upwards of 30 seconds.
It doesn't help that the demo is set in the beginning of the game and is a co-op only demo. You have to watch a mandatory cutscene, in-game cutscene (where you run around with no weapons), do some tutorials for 10+ minutes before you get into the normal action from the first game. I stuck with it because I felt bad about leaving the guy I was playing with, thinking the game would boot him as well. I eventually left at a section when the game seemed to drop to 10 or 15 fps and it was unplayable.
