Well, first of all, the thunderstep is a device which activates any dynatmite in its range whenever a talan passes by. This may be used as a trap for convoys of talans carrying resources. This potentially weakens the soldiers, depending on the thing they are carrying, at least it is suppoesd to. The fish in the water can only be killed by explosions which are caused by either dynamite already present in the water or using the boomer or the rocket launcher (forgot the name). Using the guns are easier and more practical, as dynamite are not everywhere in water. I don't quite understand what you mean by the island barracks. If you mean Zorkatraz, you can go there many times, I believe. But you ought to get the job done the first time you get there, i.e getting the booyat. The fish in okasankaar, they cant be killed, at least, I've never found out a way. The fish elsewhere can be killed using the method stated above. Don't know anything about the manual, sorry. You could try searching for it, it's quite useful.
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