Last night and today I rewrote the weapon class for Astrofighter.Net so that it can support a wide range of custom properties for each weapon. I've added about 40 properties so there will be a great number of ways to upgrade weaponry using powerups.
Here is a short video demonstrating two of the properties named "ChargeUp" and "Multiload." If "ChargeUp" is applied to a weapon you can hold the fire button down to increase the power/velocity/life of a shot. The "Multiload" upgrade allows you to hold the fire button to load X number of rounds before discharging the weapon.