If you use both area burst and ghost towers, spam all the waves, max out both of them, and give them fire rate and damage boosts, they can obliterate everything for any mode.
Play the first running minigame. Switch to a new tab on the same window. The game should keep playing and you can get insanely high scores, giving you high amounts of experience.
Graphics too intense for my computer, which causes lag and ultimately makes the hard badge harder. And whenever I am doing really well on a song, the graphics basically cover the things I'm supposed to be looking at in order to play the song. Would like a way to decrease graphic quality, either by right clicking or in the pause menu with the book.
In the last level (the one with the bug), there are only 5 differences to be clicked. When you find the 5, the sun will start shining, in which you can now see that one of the buildings is a different color than its reflection. It is possible to get the badge. I am posting this so people won't press hint on the last level.
A bit of a guide if you are struggling. Skill Tree: Get skills in this order: Sweeping Smash->Blood Siphon->Death Spell->All Crit Stats->Regeneration 2-> Any other stat upgrades. After that, you don't need anything else. Put all your souls into your sword, which will increase your damage and how much mana you get whenever you use your attack. Battle Gameplay: Regular Unit- Keep using sweeping smash until you run out of mana, then keep using your attack. Once you unlock the death spell, just keep spamming it. Strong Normal Unit- Use sweeping smash->attack->blood siphon until you run out of mana. Then spam attack. Only use death spell if you have at least 4 crit upgrades. Use health potions if you are dangerously low on health. Boss Battles- Use 2 death spells and a regular attack on your first turn. Then do a regular attack, blood siphon, then another regular attack on all of your other turns.
Found an exploit. First, get a large amount of money (if you unlocked level 30, you can play it 2 or 3 times to get $40000). Play one more level, beat it, then spend all your money. Enter another level, click pause, then exit to main menu. When you enter back in, you should have your money back and you keep your upgrades.