Hardcore isn't all that bad really but then again it depends on have good you are. You really have to be on your toes to make this easier. This sounds funny but you are almost impossible to hit if you just drive around in circles, your enemies have a real hard time hitting you. Whether its circles or in a figure eight the point is to keep moving, when you constantly change your direction they can't lock onto you. The upgrades for the machine guns help out a lot and secondary weapons, just make sure you don't die as they reset when you do. You can also hit enemies when they are off screen, just look at your score bar to see if you are hitting anything (since as long as you're hitting an enemy it will count). And remember to take your time or you will die quick, very quick. Two hits from a heavy tank or three from anything that fires a rocket and you're dead. Use caution instead of charging into an area. And stay well away from anything that spits fire.
I'm not going to say which character is best for the job since that depends on how you like to play the game, I'll just say I went with Armand. I find his shield ability to be almost invaluable, it's handy when you need to get away and the Rebound tactic makes tanks and rockets work for you. I've been using him with the Second Chance, Harden Hull, Rebound, and Efficiency-Elite abilities.
Each character comes with their own set of special abilities. So whether you use Diz's EMP, Armand's Shield, Roxy's Air Strike, or Gunnar's Heavy Gun depends entirely on how you like to crush your foes. You'll just have mix and match their offensive and defensive abilities to what works best for you.
Here's a glitch that will prove useful thanks to Insaniac85:
*This may have been patched with the update, so try at your own risk*
Originally Posted by Insaniac85
info for the hardcore-cheevo: there's a glitch in which you only have to play level 1-8 on hardcore. level 9 can be played on normal (maybe even casual).