Hey, hardcore mode doesn't actually delete your adventurers when you die, it just deletes the save file. If you die in hardcore ode, and then start a new campaign, all your items are still there, as well as your levels. Is this intentional?
Best strategy for the beginner map is to place some normal dart monkeys at the start of the game, and work up to buying Ice Towers and Boomerang Monkeys, and fully upgrading both. Place tacks or use a Tack Factory for Camo Bloons.