For the BOSS: have all three heroes' every skill upgraded to tier 4, with the mini gun and rocket's damage power (weapon craft) to tier 5. During battle, just focus on the boss. The creep waves should be taken care of by the other two themselves. This method does not require any grinding, assuming you maximize your ability to gain gold at early stages, with two times 5000 gold rewards.
Moral of the story (well, of the game): ignore the distraction "give up". Calm down and get used to each map. Once you know evey bit of the map, the whole levels become less frustrating.
Tips for hard badge: ==Height 0~150m== You can do the "image jump" to have a good start, but if you don't get what you want, just proceed casually and carefully. ==Height 150~300== Things start to get complicated in here. Don't be hasty. You will have to do short jump a lot. Don't be afraid to the laser, it usually can't catch up with you (Unless you jump too slowly). ==Height 300~destiny== This will require a lot of practices and your eye judgement. The laser will likely crush you if you keep doing as in "height 150~250". In here, sometimes you will be able to pass through two "deadly obstacles" with just A SINGLE HIGH JUMP. Miscalculation in here will make you pay a lot. Short jump or high jump, the decision is yours. --- Note that the difficulties of the height mentioned above is approximated, but the methods is still the same. I got the hard badge after playing around 1 hour. Hope this helps.
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