In defender 2 game, just go to build and bolster your in-game currency, and make you a better player.
Avoid the lightning strike.
This mana power slows down enemies and to freeze them
Then, just purchase it at level 1 of this power-up.
Take out all floating and flying enemies first.
The general rule of this game is the enemies in the air so focus on your fire and your mana attacks.
Do not underestimate isolated enemies.
They may not seem like much, but when they reach the castle wall they will be at the wall in short time. So take them out as they come.
Go for the Phantom Crossbow.
It combines the powers of the other two and is generally the better investment to make, especially at the start of the game.
Try to play wisely so you will not need castle upgrades until level 20 and more.
Just keep the enemies at bay and invest in mana powers if you do it well you will never be having to upgrade your walls until after level 20.
Just research are strength and mana research or mana powers.
Powerful shots from your bow and the fireball mana power are the best ever.
So focus on these weapons as they will be handy to defeat bosses boss level.
So use your mana powers, then spam arrows at them.
Rinse and repeat to get the victory of battling with the bosses