This
was honestly the best game I've played on Newgrounds. One of the best games I've played in a browser. It's seriously been a long time since I've just sat and played a flash game for as long as this. My suggestions for the second one would be first off, to have all the weapons combine in different ways, two at a time, like in Gunstar Heroes. You could even just keep the same weapons as in this, and have them each work with each other. Also, don't make them impermanent, instead just have temporary power ups. Second, I just have to say to make more of everything. More upgrades, levels, ships, bosses, enemies. Variety is what will make it great.