for epic bosses, what I do is just get some water to slow him down even more... I set up extra empty towers and move my gems over, if he still passes the defense, I throw those gems at him until he dies. Cheers :)
To kill the flail guy for gladiator just jump right on top of him (i.e. on the space that he is standing). He will swing wildly but will be unable to hit you until he breaks free, at which point just jump on top of him again.
I found the sword+shield guy to be the hardest by far to kill. Took me several minutes at least :(
here are some tips for that hard badge:
1) relax
2) don't focus on the enemy. just hold spacebar in the general direction and focus on dodging on the ground (in the later levels you may have to rise a bit...)
3) make use of peripheral vision
4) the invaders don't shoot constantly but in bursts (some of them pretty long I'll admit), look for breaks and make use of them to shift positions
5) collect hearts. As many as you possibly can, cause chances are it's going to be pretty tight at level 7+
6) practice :P
cheers
If you want a good strategy for the impossible badge, go here:
http://www.kongregate.com/forums/3/topics/2483
It will take a few tries to get the hang of juggling the 3 exits but once you get it it's very easy to get the 12k. Cheers! :)
For headache badge I suggest you do the following:
1. Find a relatively flat area.
2. Jump right on top of the shell so that it flies straight up
3. To juggle, jump a little bit earlier to hit the shell (i.e. hit it when it's not close to your head so it doesn't fly up very high) and it'll be easier to control.
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