Yeah, I've been playing this for a year with my friend in co-op every couple of weeks; we're about 2 play sessions from finishing the game. I just got a laser freaking chainsaw.
Here's my impressions:
+Flying girl is back and just as fun to use as EDF2. I still don't get how anyone could enjoy any other class but my friend still plays soldier like he did in EDF2 while I was flying girl.
+It's EDF, bugs are still fun to kill, loot is still cool
+Lots of weapons
+Graphics and framerate are EDF, yay!
+About 100 stages, some cool new enemy types
+Online 4p, this is probably awesome, but I never had anyone to play with online so stuck to 2p local
+/- Ok, so you got 2 new classes with their own gameplay and set of 100s of weapons like Soldier man and Flying Girl. The problem is they are both pretty flawed and most people will never touch them so it's almost a pointless addition. Engineer guy makes vehicles, calls in airstrikes, etc... he's a great support unit for the other players...but he's only really playable in groups as a SUPPORT GUY, meaning playing online with 3 other people, on his own he's like the soldier class but horribly shitty version and he dies FAST, even in split-screen co-op he's not really useful enough to be used. Then you have the ROBO-FENCER guy who has all these badass powerful weapons like a GIANT HAMMER or defensive stuff like shields, but he controls like shit and is incredibly slow and annoying to use. You can move slow as a rock (flying girl movement >>>>>>>>>>>>>>>>>>>>>>> Solider/Mechanic >>>>>>>>>>>>>>>> Fencer) or you can do these shitty dashes. He's definitely the strongest in the game, but he's just not fun to play as, just like how the support engineer isn't fun to play as. So in the end you just stick with Solider/Flying girl just like EDF2 and that's cool cause EDF2 rocked.
-Not that many new enemy types if you played EDF2/3. There's a few, but there's like 100 stages and you go six-ten stages fighting the same enemies before they introduce a new one and it takes till like halfway through the game before you start seeing some new ones and then they milk them for all they're worth. Some cool giant robots, but so far around 75 stages in there's nothing as cool as the Godzillas and giant Centipede's of EDF2. And the robots, while cool, were already played to death in EDF3.
-There's a lot of weapons, but I feel like they're aren't enough unique and varied ones. Playing their Wii Fantasy EDF game, Reginleiv, I saw a lot of kickass cool weapons that I would've liked implemented in EDF, but this generally sticks pretty standard to the old weapons. Flying girl is lasers, plasma launchers, lighting sniper rifles, etc....
-Load times are lolz
Overall it's a good entry but it does feel like they're coasting from EDF3. It's basically EDF3 with the stuff missing from EDF2 and some additions. Worth playing for sure if you're a fan of the series, but kind of hoping EDF5 will mix it up a little bit. Also EDF3, though gimped without my flying girl, felt like a bigger leap because the graphical jump and mechs and robots first being introduced. Would like a jump like that next time. EDF4 is an iteration.