Thank you for trying our game! I agree that the text at the start are scary, but we were low on time and just needed to get some instructions in. We've thought about having smaller levels, but we had kept the single level that the player returns to in order to fit the theme. The goal of the game is to collect enough loot and items and return to the glowing portal, killing enemies are optional for extra gold.
As for the boomerang and attacks, you'll need to select Action and Right click to where to aim the attack first before clicking Attack, we should have made it a lot more clearing with it, sorry for the confusion.