Just go along the path, collect the antidotes and the hearts in the barrels. Then talk to the mechanic.
For the race, I can not give you too many tips. Just accelerate and sometimes break at the sharp corners” in order not to hit the walls. It should be easy to finish the race being second or third position.
The job is clear: You have to destroy five rocket launchers. How do you do this? Well, collect one of the blue flashlights moving around on the floor. This is the tricky part of this level. It is very difficult to catch them. Be patient and try again and again. Once you have a blue aura around your quad, look for the yellow rocket launchers. Hit one and it will explode. Once they do so they will loose a CUBWHEEL. You will find three rocket launchers on the ground level.
You noticed the two big towers on the field. There are ramps around them leading up. Use them. Once you are upstairs take the path to the central area where you hopefully will find a flashlight. Pick it up and destroy the final two rocket launchers. They are on the top of the two towers. Pick up the CUBWHEELS and have a look at your radar. Drive to the blinking green point and you are finished with this area. This one is done.
Finally, a jump-and-run-passage again. There is a lot to do here.
First use the purple barrel to your right to get the first FEATHER.
Continue your way to the right and you will pass some burning barrels. Now where is the shield dragon? You will find it if you go a stairway up to the right, near the ocean. There is a purple barrel and a burning barrel nearby. Now destroy all the burning barrels you saw on your way to receive a FEATHER and a KEY.
In front of the big ship there are some guards. Get rid of them in order to receive a KEY. A little left of that you will be able to jump on the roof of a house (there are some antidotes on it. Between four explosive barrels there is a shielded barrel with a FEATHER inside.
Near the passageway being full of mines you will find another accessable roof. You will find a KEY in the barrel.
You noticed the mass of guards walking along a balcony in the middle of the town? Take them out to receive the final two KEYS. Yes, got em all. Now examine the balcony. You will find a shielded barrel containing a FEATHER.
For the last FEATHER, go to the place where you found the shield dragon (you know, this stairway in the right part of the town. Use the purple barrel to jump high up.
Now for the RUNESTONE: You notice the device nearby, don't you? You need energy in order to make it operate. Pick up the shooting item and shoot the purple barrel you just used. Shoot it many times and you will get shield energy. Now use it at the device and you will be taken to the locked barrel. Found the RUNESTONE!
But we are not here in order to collect RUNESTONES, we have to get a ship to Hero's Island. So go to the harbor and talk to the captain of the ship. Perhaps this is a good opportunity to get rid of the mines. Pick up the shooting item left of the ship and shoot them. The captain will tell you what to do.
First, ring the bell on the town square. Talon will help you.
Now cut the three chains holding the ship. This is easy: One chain is to the left of the ship, one in front of it and one to the captain's right.
The last job takes some time. Go onto the ship and you will find some kind of trapdoor. You will see some energy devices down here. Your job is it to run around and use your shield energy in order to load the four devices. You will need much energy for that. Once you run out of that simply leave the ship, take the stairway ahead of you and jump into the purple barrel. Then return to the ship and continue loading up the devices.
One more thing: Pick up so many antidotes until you have 79. Believe me, you will need them in the next mission...