This is a really great game. For one, the concept behind the game is well-executed--it's a top-down shooter, but you're free to explore the world around you. I think the open world works great in this game because it really encourages exploration, and it supports the fantastic upgrade system. This is the reason why I, like some other players whose reviews I've read, played through this whole game in one sitting. It took me hours--but I was that hooked!
Also, the style and attention to detail in this game make it all the more appealing--every object is made out of gridlines, but the coloring and even textures (look at the BIG asteroids) on each object makes the appearance of the game much richer while maintaining that fresh, arcade-like quality. Plus, the music was EXCELLENT. Whenever you begin a final mission for a certain location, it opens with this chilling synth that really makes it feel like you've gotta concentrate or else you're gonna die!
But, while this game is nearly flawless, I did have some issues with it. First of all, the difficulty labels seemed a little inconsistent to me. I found that I couldn't beat most missions against the Augustan Military (these are pretty hard missions) labeled "Medium," but it was a breeze taking down the final enemy in the arena--a mission that was labeled "Hard." There were a few other instances where I found missions to be impossibly difficult despite being labelled otherwise or vice versa. Also, at one point in the game--maybe three fourths in--I found one station where you could blast away to earn 1,000 credits (this was also a mission labelled "Hard" but was pretty easy), so I grinded out the mission over and over until I had 18.000 credits--enough to buy a +2 power upgrade. After that, I was practically invincible. I beat a few other missions and bought more upgrades, and I didn't lose a single mission after that. This made the last quarter of the game a bit tedious, since the levels weren't very challenging.
But, other than that, this game does its job very well. Most top-down shooters do get tiresome very quickly. Now, it is true that this game got a little tiresome after I upgraded to a point where I effectively broke the game, but this game captured my attention much longer, thanks to an incredible upgrade system and the impeccable presentation (art, music). Other than the small problems that I had with this game, it was a thrill to play, and I'd love to see more from you!