Can you guess which of the following sprites is from SMB1 and which is from SMB3?
Tougher than you thought? Yes the one on the left, despite being more detailed, is from SMB1. The real upgrade that Bullet Bill got was in the gameplay variety. In SMB3 there are now Missile Bill variant that if they miss you will turn around in mid-air and try again. They flash brightly and make a the Bill family a bit more dangerous as a whole.