I had a lot of fun testing this game. I'm an avid fan of shmups, not exactly the most hardcore player, but as one of Colorvade's testers he was very responsive to testing and balance suggestions. I'm not the only one who he's given respect to feedback for, several reviewers here on NG had issues that he tried to fix.
Overall, I'd give this game a 3.5 or 4 for being so fun to play for an arcade style shmup (I'm bored to tears by most of them) and while I'm not blown away because of the restrictions of the genre itself - I'm sure he'd make a much deeper and tactically interesting game given more time - the game's pseudo/randomness factor and the fact that he responds so gracefully to legitimate criticism give the game a very high score in my book. The game's not perfect and has its share of flaws, but given the short time he was given to work on this game and the restrictions he gave himself, it's beautifully well-made.
I'm aware there are certain issues that come out of the game's random factor, like getting stuck between two hard places and having a rock flying at you, that would never exist in a shmup with manually designed stages. I feel like Colorvade could have given more attention to issues an added more ways to bandaid them. The recent inclusion of continues and not de-leveling when hit by bosses help with most of the game's problems, but I feel like there could have been more done with the controls and meta to make it more pleasant, like a slowdown button that shows your hitbox, spawning with a single bomb to get you out of tight situations at the very beginning of the game (I restart early /all/ the time because of them), and displaying a cursor for mouse control mode. Those would have benefited the game a lot. Oh, and a mouse button for bombing, and some way to save my options. Overall the game has its share of flaws even considering the developer's situation, and I hope that he continues to update and support the game as time goes on. This is why I'm giving the game a 4.5/5 instead of a 5.
There are a lot of people citing performance issues as a reason for giving the game a low score; I don't see the logic behind this, partly because I have a downright horrible computer and still manage run it completely smoothly whenever I'm not running something horribly intensive like a Gamecube emulator in the background, and also because Stencyl itself is prone to performance issues due to its physics engine and lack of optimization/removal of bottlenecks in some margins.