The power ups are all decent, but I have some suggestions for the second. 1st, the penetration power up should have a graphic or a different color to make it more fun. As it is now, you never know if it is working or not. Since, in order to get big multipliers, you need to slow down the leveling process, and later in the game it is better to level quickly to refill your health, let us burn some points in making them drop more or less pixels, rather than just more. The final "spread" point is underwealming because it takes away the three bullets center fire, and is only usefull later on when monsters are huge and close all the time. Consider making an ability to spend points that increase the drop rates of all the power ups. The game becomes very difficult after level 25 or so, about perfect for the amount of time it gets there if you try to level very slowly. Great game, still waiting on the second!
OK, here's some thoughts on Pixel Purge and what I think should be in the second. I have played the heck out of this game, at least 5-6 times a week. I like that it is a simple concept "high score" game. I like that it is better to NOT level, as the game quickly becomes impossible if you blow through the levels. It is an interesting twist, and Im not sure if it was really intended, but it makes the game interesting and different.
 "Pixel Purge"){kind=icon}
 "Arkandian Crusade"){kind=icon}
 "IQ Ball"){kind=icon}
 "Doodle God"){kind=icon}
 "Paradox Embrace"){kind=icon}
 "Spewer"){kind=icon}
 "Reincarnation: Riley's Out Again"){kind=icon}
 "Bunny Invasion: Easter Special"){kind=icon}
 "Don't Look Back"){kind=icon}
 "Exploit"){kind=icon}
 "Crabs!"){kind=icon}
 "Shooter Game(invisible mouse)"){kind=icon}
 "Dolphin Olympics 2"){kind=icon}
 "Jump N Bump 3D"){kind=icon}
 "The Implausible Quiz"){kind=icon}
 "Meet people in traffic"){kind=icon}
 "Samosis"){kind=icon}