When you die you start with the same health you had at the beginning of the level.
But, yeah, probably it's a bit too hard.
I've updated the game, now you got a higher life bonus at level up and health boxes drop more frequently.
Thanks for feedback!
I really like the game but holding the mouse button the whole time is difficult. Maybe when one rests (aka no mouse button) it can recharge shields or power up a totally awesome weapon blast.
 "That's What She Said?!")
 "Transformice")
 "Rampant")
 "Sprite Examples")
 "Magical Glory")
 "Winged Sentries")
 "Oh No... Goblins!")
 "Dragon Bow")
 "Cannonball Max")
 "NotePad Wars")
 "Water Run"){kind=icon}
 "flash game test")
 "American Tank: Zombie Invasion")
 "Hidden Object - Candyland")
 "Nordic Chill")
 "Castle Kong")
 "The Miner")
 "Super Hammer")
 "Planetarium Demo")
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it should be fixed now