TO RECIEVE FULL HEAL just buy a new armor. Keep some money, sell one armor (doesn't matter what kind of armor or who dress it) and equip the new ;) Keep it alive
Just a bug to qualify, it's impossible to do better than the last place, but... Easy. Take the pilot under the half of the speed bar, look at the race tips, train the pit crew at top, and the only keys you have to push will be "A,W,Q" and look at the clime during tha race. If it change, make a pit stop to change tires. Doesn't matter if you start at the bottom of the startline, you will win. Oh and... pay the research well.
It starts to be too much hard at the 3rd level. Pretty, but with some things could be better. The shotgun reloading makes nearly impossible to change weapon during the action, and the zombies, at higher levels, are too much resistent (i have to use 6-7 shoots of sk47 to take down the biggers... it's too much).