This is a cool game. Nice platform design, funny introduction and endings, there is even small things that change a lot of things like this shader effect on screen border which is very smooth! Lets talk about game design, I think that due to the nature of the platforms you created, you should have thought about making the balls more affected by gravity, just as player for exemple: like I'm on a platform and the virus in on another one in front of me but in a higher level, I could shoot and find the perfect angle and the ball would fall on him just like a baloon; and even like this the mechanic you add in level 4 would not be changed. And lets talk about animations, they are nice, player and virus are tiny and still moving while not having a speed that's a detail that count a lot, but why not adding an animation or shading effect when ennemies are touched by the ball, it is not evident if we hurt them like that; in the first place I thought we cannot kill ennemies! And also I see that 3 hp for ennemies make the game really slooow. Also for animation (well, it's just a little detail) I wanna talk about the two animations of player when he jumps: there is one shown if he is puched up and one when he is falling. This second one is just done by reversing the image (I think) and I found it brutal, you could for example make the y scale decrease fastly in each frame until it's the opposite number, It would have been better! For bugs, there is one after the boss, I passed the duel without doing it. Overall that's a very good game, and an underrated one! Good work!