Cool game, VERY interesting history and mechanics (particularly drone system) however the game becomes a bit repetitive.
Can be hacked with GE for great amounts of experience. Did it after I realized I could NEVER complete it without investing an amount of time I do not have. Didn't affect negatively my experience (On the contrary!)
Excelent overall, however the difficulty curve is very accentuated. Shield regen is a "trap", as to stop firing causes drones to flood the screen.
Improvements I suggest: Different weapon configurations. Spread could had been switched to instead of a power up (cannons can compensate for momentum, so why not spread by selection?) and also a bomb would been nice sometimes.
Greatest pros: Music, mechanics, history, upgrade system.
The only flaws I really consider you MUST pay attention on the sequel (do a sequel): The game becomes very repetitive and difficulty rises a LOT faster than it should.
IMHO, flash games should NEVER be based on farming/grinding (those "IDLE" games are an exception, that's their point), since it attends mostly casual gamers (as me!), and as casuals, we may not have time to invest on grinding. Grinding is the worst RPG element ever conceived. It is just BAD. Grinding is bad, so having to grind is bad too. Do not make grinding based flash. It is bad. It's an outdated RPG concept that goes back to NES and older consoles, since lone kids had nothing to do with their time so they could grind on breathes of fire and final fantasies.
Gaming is about challenge. Not grinding. Say NO to grinding based games. do that and you are fine.