To get the Hard Badge (and 100% completion after FIVE 99% runs), I got all of the medals and level 10 so I had $3,615 to start.
At the beginning of the game, I upgrade the ship twice and buy the Level 4 Loot/Magnet and Level 3 Weapon. After the first boss, I bought the Level 4 Flag. Before the final boss, I sold the flag and the L3 Weapon and bought the Level 4 Speed and Level 4 Weapon. After the 3rd boss, I bought the next ship upgrade and the Level 4 Flag. 3 Final Bosses later, I had 30,000.
To get 30.000 points, I used 2 ninjas, a fairy, and a cat.
Wave 18 was almost the end for me, but I used my special JUST ENOUGH to get 30010 points before the screen faded completely to black. Good luck if this helps you.
If anyone needs help getting past level 19, you should place all your ground towers in a diagonal line across the field and hit the tanks while they're being hit by the towers. Position the air towers parallel to the top of the field and the mines scattered throughout.
I think an upgrade that increases the drop rate of power-ups along with the rate of crits and piercing bullets would be a good idea. Also, an "Easy" or "Infinite" mode would GREATLY increase the fun to be had in this game.
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