You can press the mouse to add the points and change the stage slider for next level. You can simulate light by setting the gravity to 0 and setting the velocity of it to much higher value It would lag when there are many particles and also I failed to implement mass, friction, restitution, and linking.
I know it's been long since I posted a new project, Sorry. I had so much to study for my exams.... When I looked scratch after so much time, I found that I had more than 30,000 messages !!! Thank you guys for supporting me :D