One thing i forgot:
The enemys off screen are hittable by your main weapon. The arrows are showing where you would have to aim with you cannon to hit the enemy if it wouldnt move.
I dont know why everybody is complaining about the difficulty...
The Asteroids in Chapter 2 are no problem even at hard difficulty. You`re doing something wrong then.
Look at the strategy guide. This could help. It`s important to upgrade your main weapon early and often and practice some shooting skills to hit the fast little ships. Later you`re shooting on capital ships mainly. Use your Fighters for distraction and dont level them on attack so much.
I made the hard badge mainly upgrading my main cannon and having the fighter bays upgradet in number of ships and rebuild time. Repair drones are important but dont level them too early. If you have enough fire-power you wont need them early. I used some flak towers (3) at the edges of my ship to destroy fighters and the rest of slots were laser towers. Build those towers late in game.
Tip: Dont use the first few tower slots in the front of the ship because towers in these slots will be destroyed by enemy fire very fast.
This game is great. Way better than the first i think.
Best is that you have so many possibilities to upgrade your troops, changing race and so on. And the way of achieving new troops is cool. The bosses are challenging too. 5/5
 "Super Xtreme 5 Minute Shoot Em Up"){kind=icon}
 "Get Off My Lawn"){kind=icon}
 "Youda Marina"){kind=icon}
 "Phage Wars 2"){kind=icon}
 "Ancient Warrior"){kind=icon}
 "Orbital Decay"){kind=icon}
 "Canyon Defense"){kind=icon}
 "Streamline"){kind=icon}
 "Talesworth Arena: Death Watch"){kind=icon}
 "Epic War 2"){kind=icon}
 "Destroy All Zombies III"){kind=icon}
 "3000 AD"){kind=icon}
 "Nano War"){kind=icon}