Additional bonus points
Complete a level. You will be at the "BREAK TIME" screen. Now when the music stops at the "BREAK TIME" screen, jump. As long as Pac-Man is still in the air when the game stops, you will earn an additional 10-7650 bonus points along with the bonus points you get for the remaining time that wasn't used while in a level. The amount of points you get depends on how close Pac-Man is to the ground when he lands without touching it. You can do this at the end of every level.
Pac-Man with L item
First, make sure 4 ghosts are on the screen. Then, move a little bit to the left so Sue (The purple ghost that appears if you stand around, go left, etc.) appears on the screen. Eat a Power Pellet (The Power Pellet MUST be on the screen with the 5 ghosts), then eat all ghosts except for Sue. When you have eaten 4 ghosts, eat Sue (Sue MUST be the fifth ghost eaten). A small Pac-Man icon with an L will appear. Collect this item and you will earn additional points and the time limit icons on the top of the screen will be completely refilled, giving you more time to search the levels.
Purple flower
In any Round (level), wait until you have run out of time. "TIME OUT" will appear on the top left of the screen and a purple flower will fall from the top of the screen. Collect the flower and 300 points will be added to your score. This is the only way to get this rare item.
Skip to stage 13
In stage 1, if you collect at least 10,000 points, don't let the time run out, AND finish the stage while being as high up as possible, you will warp to stage 13 instantly instead of continuing to stage 2. Note that if you have a hard hat, you will lose it this way. The easiest way to do this is to collect at least 4 cherries, and when you get to the Power Pellet, stop to the left of it, and then wait for Sue (the purple ghost) to get very close to you. Then walk right to the next fire hydrant, and if you did it right, all four other ghosts will come in from the right. Wait a bit until they are nicely in frame, go back to the left, grab the Power Pellet, and eat all five ghosts. Then, if you're still invincible, you can go some more to the left and jump on top of the smaller house, which you can use as a stepping stone for the taller buildings to finish the stage as high up as possible. If you take too long, you can still use Sue to get on top of the buildings. By the time you finish the stage, you should have little over 10,000 points this way.
Additional bonus points...