The Final Mission!
If you've not continued yet, you're doing really well! Keep it up!
Once you start Mission 7, there will be a Tank awaiting your arrival! If looked after right, you can keep the tank for just over half of the mission. Of course, the difficulty is still pretty high even being in the tank but at least you can take a few hits and have more firepower than you would if you were on foot.
The action is continuously heavy throughout almost all of the mission so make sure you take your time, move forward slowly and focus on the biggest threats within each situation.
Should you lose your tank at anytime in the mission, you will have to carry on foot without the aid of a vehicle as only the one tank is available at the start. There's also only one cannister of Gas to be found in the second section of the Mission which fixes a third of your tank's health if you've recieved any damage. Hyakutaro Ichimonji will aid you in the second section, but of course, don't count on him to do all the work for you.
Once you reach the boss, the pressure is truly on as you must fight on top of junk platforms floating on life-ending lava/water. Keep your cool and learn what its attacks will be! Check out this video for tips and tricks on how to pass this level without continuing.