Every time Dude levels up, he gains two skill points to be used for leveling up. Each skill has three levels (the first level requires 1 skill point to learn, the second uses two and the third uses three) –if you concentrate on maxing out a single skill at a time, then you will max it out within three levels.
Our biggest recommendations are Experience up and Money up. These two will make your progress a lot easier–you earn skills and make money faster this way. Get the exp bonus first then go for the money. This will help you earn other skills and buy those powerful guns as early as possible.
The next most recommended skill to learn is HP regeneration –this will help you conserve money from buying those medi-kits. Upgrading this skill to max level will give you a bit of a health boost in between each stage and whenever you jump on top of the car. Most importantly, regenerating HP means you get to stay alive longer.
The value of the other skills depends on your play style. Accuracy is pretty good for players who want to lessen the spread of their shots –but if you prefer to take advantage of the spread (particularly when dealing with mobs), then there really is no point in concentrating on this one. Faster repairs do exactly as described –it makes the repair process significantly faster. If you are only playing to finish the game, then max it out –but if you are playing for the long run, then there really is no rush speeding this up as it would end the game as soon as the car is fully fixed.
More effective health kits are nice –particularly in the late game and if you have taken plenty of damage (early on, when your max life is still low, this is not good to invest skill points on). Higher car armor on the other hand, is a giant lifesaver, particularly when you reach later waves where the giant type zombies really start swarming in.
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