I have prevailed.
I had missed the weapon charging at first and just kept the button pressed so I could not manage to beat the skulls. After reading the game description and a couple of extra retries I managed to keep my power all along the game and eventually win.
The game looks and sounds good and it is very fun, the controls and feedback work, the roster of enemies and enemy formations is good for the scope of the game and the difficulty is right on point.
Very cool work, thanks for sharing.