I only wish it were a little bit slower in the first levels. Anyways it's an awesome polished work! Congratulations!
Clear the path in front of your microscopic submarine before the next hearth-beat send the blood particles crashing your way! Use the mouse to drag the blood particles around, create matches to remove particles from the vein. You can move your submarine too (either by dragging or with the arrow keys). Survive as long as you can!