The contrast on my laptop's screen leaves much to be desired- dark blue and green enemies on a black and dark grey backround are very difficult to see. Adding an outline in a high-contrast color would have made dying from being rammed by enemies you could barely make out clearly might cause some people to ragequit. The bullets can be clearly made out on all the levels (that I saw...) at least...
The opportunity cost of trying different powerups/levels is very high, measured in player time spent.
I second the comments about a minimap- or at least a distance measurement from where you're at to the finish. Either would aid in learning the tracks. Tips might not hurt; not silly things that might not even apply given the games physics (like "slow in, fast out" or "pass on the inside"), but track specific tips like "the key to winning at Turkey is to maximize your speed through the long high speed turn" or suggestions about where to use your boost on the various tracks.
When the powerup appears (I only saw it once!), there ought to be an audio cue- a more eye-catching, animated sprite for it wouldn't hurt either. I second the critiques in the other comments. This game had something that saved it from the abyss of a 1/5 rating; it is probable that with a few tweaks this would be a solid 3 or 4.
BAG (Barely A Game). It has a score, but it doesn't save it. There is no victory condition, so its merely a competition against your own boredom. On a 1000:1 LCD monitor, there wasn't enough contrast to make out enemy and especially player bullets against the black backround; if you like the color, try adding a lighter border around the bullets to make them "pop" more. Provisional 1/5, but it could be improved easily.
The ingame purchase bit doesn't bother me in principle, but when its positioned onscreen in a fashion where you accidentally click it all the time... well that doesn't help. The zoom buttons do nothing. Often, the map won't scroll automatically and there is no manual control. Buildings built on the northmost corner of the map have their description bubbles appear outside of the screen. 1/5, if you expect people to pay money for it try harder.
2/5. The music and SE could be mastered at a lower volume. Only the nice shooting mechanic, the charging bar which gives you faster shots, keeps this game from slipping into the abyss of 1/5. If that mechanic were expanded upon, say a screen clearing attack that completely drains the bar from full, the ability to charge up a single shot (accompanied by the occasional tougher enemy), or powerups that gave you another weapon in addition to your normal shot (but drained the meter faster), this game would eke out another star for 3/5. With a slight graphical overhaul and more varied sound effects and music, this would be a solid 4/5 and a strong contender for 5/5.
More like Minesweeper meets Guess Who, but a thoroughly enjoyable mashup! Reminds me of Oasis by Mind Control Software, in that it implements the minesweeper mechanic, but offers more forgiving gameplay. 5/5
Needs badges A++ would not play again :-P Effective enough to score well, but you lose a point for having an exit/win state- collecting everything, dying and having a score as the only end state for the game would have been an artistic statement at least (death being the only way to quit or be scored). Global rankings would have emphasized the artistic statement I feel this makes, and would be worth another point. Appropriate player sprite, music, and sound effects would have earned another point. 3/5
An awesome translation of the basic game mechanic from Sega's Afterburner games to top down space shooters. This needs bonus stages, a better soundtrack, or more variation to hold interest. I kept going for quite awhile, hoping to see something other than ever more difficult patterns! A bit more polish in the aforementioned areas would have earned an extra star. 3/5
Kreds for upgrades would be fine if it stripped the ability to earn badges, and any previously earned badges on that game from the player's profile. The kreds thing is an issue that knocks off a star, the save-only-with-mochi-logon is another star off. 3/5