OMG
LODE RUNNER! That was one of my all-time fave games way back when we had a Commodore 64. Yeah, that's how old I am.

My brother and I would play it for hours. lol
Anyway, it's a SUPER easy game! I got to 650 pts by Level 2 by trapping the ghost over and over, getting the bonuses, and then running out of time (you have 4+ minutes in the early levels, 6+ min in level 5 and higher). The bonuses accumulate in the game, and don't disappear after a few short seconds, so you can rack up a ton of points by getting the money bags and lots of lives getting the books. This allows you to play the same level over and over again and not have to worry about running out of lives (unless you die before you get more books).
The key to getting the ghost is to shoot two holes next to each other in between you and the ghost. The ghost will fall into the first for 3 points, then he'll get out and drop into the second for another 3 pts. If either hole closes up on him you'll score an additional 5 points - for a total of 11 points per ghost. Sometimes a third hole is needed, but 2 usually did the trick. BE CAREFUL on the bottom floor, if you fall in the hole you cannot get out, you'll die once the hole closes. In the real game, ghosts will fall down through holes to lower floors, like you do. In this game, they don't, they will just stay in the hole on that floor.
I was able to get the score to get all collectibles by Level 3 and then just wouldn't take the whole time to pass levels just to see what higher ones looked like. With all the hour glasses you get, it's very difficult to run out of time. So if you want to get most of your points on easy levels, I suggest taking all the time to get as many points as you can from trapping ghosts and the money bags, then letting time run out. Do it over and over, and like I said, I got to 650 pts in level 2 before I decided to just move on. It's a really easy game, though. I don't think I went higher than level 6 or 7, so I don't know how difficult it gets later on.
Anyway, hope that helps!
~Vicks