Probably the most fun I've had playing an entry yet.

Good gameplay!
These green triangles are so horrible!! :D

Neat game; I liked the dual shooting and moving controls, and you implemented them well. Lots of stuff on the screen. I felt like when I bought my first upgrade, I actually got more than one, since I suddenly had blue, purple, and green shots all at once, and I thought I was only buying one thing. Once I had those, the game got a lot easier. Fun one, and good work.

This is a nice shooter. I felt that the art did little to aid the player in distinguishing the character, enemies, and projectiles. Other than the tough visual recognition part, the gameplay was quite enjoyable.

Good job.

Simple but nice :) Had fun with it.

Loved the music on this one! Gameplay was nice too :D

Very, very good entry, congratulations! What I like about this is that it is really a game and nothing else. You don't play to see the next graphics, to hear the new music or to know more about the story. It just has you playing it because it's fun to survive while intercalating moments of stress (when totally surrounded) and relief (right after getting an upgrade and feeling a sensible enhancement in your own power). This is the best entry I've played so far on what regards playing by itself, this is pure gameplay!

Things I'd suggest if you ever wanna make a post compo or complete game out of this:
1. As Mes said, visual recognition is an issue. Maybe you could have visual effects that have no effect on gameplay (like smoke, blood, etc) at a low saturation color close to the background; enemies and their projectiles in another range of hue, and so on. The most common problem I had was red enemies versus particles of blood, and my own homing magic bubbles versus the blue enemies' bullets. The mouse cursor was pretty easy to lose track too, specially in later waves.
2. Upgrades make a big difference at the beginning but you lose interest in them after a while because the 'power leap' you feel when you gain a level decreases. I feel that both your power and the enemies' don't keep escalating at the same speed after a while, so which power up you pick becomes kinda irrelevant in later stages.

Still, one of the best entries I've rated. Congratulations, and PLEASE tweet me if you ever develop a complete version out of this! @pixel_cows

ps.: You might wanna check out our entry, it's very gameplay / upgrade based too! ;)

Cheers from Brazil