Bookcase Battle: Cash & Upgrade

Game description:

If you're low on funds, you can replay earlier levels to earn more money. This will allow you to purchase or upgrade weapons so that you can progress further in the game. Another way to earn money is to complete challenges. These challenges can be found in the "Challenges" menu. Completing challenges will reward you with money, experience, and other items.

Game controls:

Player 1:
Arrow Down, Arrow Up Move angle and Arrow Left Arrow Right Move direction and Space Keys Fire