Interesting game, but some bugs/confusion.
The game was a lot of fun, and definitely worth playing for a while; very addicting. I did run into one problem with the upgrade system though, specifically for the circles. I'm assuming that each level of the "increases by 25% chance upgrade" means that it increases the chance of that particular event occuring, such as the triangles firing a third time, or the circles doing double damage. However, I upgraded the circle's doing double damage up to the max level, level 3, and yet they still only did their double damage about 25% of the time, making it either a confusing upgrade, or a broken one.