Just after posting this review, I got a new high score of 472 million... but once again, 208 million of those points were from video mode! Definitely not an ideal balance.

don't worry, the real points doesn't come from the video mode. Once you're more comfortable with the table, the strategies for making bigger points become more apparent.
For example, try waiting around in the first time era and completing everything there before changing to the next. For example, if you successfully complete the two challenges in the first era (the side loop) and ride the loop the extra times needed to light all the continents you can start up world domination mode, which in conjunction with a time frenzy (time it with the super time frenzy light on the left for a perfect one) you can rack up some serious points! (go for the spinner and then the side loop and you'll get billions of points if you're really successful). If you manage a combination like that and then don't die you'll probably have very large bonus multiplier which alone will give you hundreds of millions after you die. And that's just one combination, the table offers lots of variability like that.

Good to hear it. My problem right now is that I have a lot of trouble hitting the upper ramp. In my high score game I just mentioned, I didn't complete a single exploration.

Yes, that upper side loop is hard to hit! A tip though: If you catch the ball with the right flipper (making it stop, while holding down the button), it's much easier to make a predictable shot through the loop behind the gem and then using the side flipper to try and hit the side loop. After a couple of tries you'll notice that the timing is almost always the same for hitting the loop.
Also, if you've already activated the locks for the time machine, but sitll want to hit the side loop using the aforementioned technique do this:
Catch the ball with the right flipper as usual, then while still holding the right flipper, press the left flipper as well. This temporarily disables the "lock" ramp that's lit for the time machine, thus making you able to make that shot behind the gem to access the side flipper and side loop again. This is especially good if you've not yet completed the challenges in the current era, but activated the time machine and don't want to switch time yet (maybe you've got that global domination mode just ahead).
Also, when you do the time machine frenzy, the amount of jackpots you achieve is very important, since if you get enough, you can get a time crystal, which is what you need to do in every time era to access the final mode of the game. And it's a hassle to have to change time era to a previously visited one just to get that crystal if you didn't get it before.
Just some small tips :)

Yeah I've been doing the catch-spinner-upper ramp combo, I just have trouble being consistent because the ball ends up flying by the upper flipper so fast.
I didn't know about the tip for disabling the lock though, that will be helpful.

if you (or anyone else) need any other tips just ask, I still remember some from the old days when i played hours every day :)

Gah, another 450 million point game, and I hit the upper ramp all of once during the entire 20 minutes (I lit africa... didn't even start an exploration). I simply cannot hit that ramp.

I think part of the reason you are finding the table unbalanced, to be frank, is simply because you're not very good at it yet :) It's a very challenging table, and you should be pulling 500 million a ball, probably more. I'm not quite that good yet either. You can get points far faster and easier by completing the boards challenges (like climb mt rushmore and you get 60 or 100 million points), or scoring 5 or 6 jackpots in a row on a frenzy than you can get in the video mode.
I have a few questions, just had one of my better games, nearly 300 million on the first ball. Not a single video mode either.
Speaking of which, is there a third level to it? I never manage to get a perfect run on the second level, always miss at least one of the things at varying points on the second run, almost never miss on the first run. Okay, here's a few questions if there's any takers.
How do you access the manual that explains the game's rules? Perhaps that would help me, but I can't seem to find it, in the options it just takes me to a screenshot of the card on the pinball table, but is there something more elaborate than that?
How do you do magno-save? It says you activate it when the balls falling down the right ramp, but everything I use it the ball continues down in to the bottom of the screen off the field.
Once you get the progressive jackpots, and unlock the crystal (which I finally did), how do you collect it? I see a green arrow on the way top right, above the place where you can raise the bonus multipliers, but I have no idea what ramp gets the ball through there.
Where do you go to collect the extra ball when it's lit? Doesn't happen that often (only once), and I had no idea where it was.
Is there a way to get the quick shot easier? It's probably my hardest shot on the table. I always trigger it to activate the timer, but almost never collect. On a typical game I can get it to 50-60 million, by activating 4 or 5 times, but I typically can't collect it more than once.

There is a third level to the video mode. And a fourth if I remember correctly. I usually get to the third in video mode.
450 million is nothing to write home about. I regularly break 800 million when I don't do something stupid and have broken a billion several times.
Magnosave = backspace
You collect the fragment (crystal) by hitting the crystal. You also collect extra balls this way.
Quick shot is the hardest shot in the game and it's really just down to practice. Letting the ball fall down the right side, holding the right flipper and then smacking it up when it skips over the onto the left *sometimes* works, but it's not fool proof. There is a point where it simply feels right. It's possible, and I've done this many times, to hit it straight away as soon as quick shot is activated and it rolls down fast to the left flipper. Difficult though.
The big points are gained by progressing though time.
Here's how it works:
You start in the present. You have two available explorations, Europe and North America. (Channel tunnel and mount rushmore) Europe is very easy since you don't need to hit all ramps to get good points. North America isn't too bad and it's actually possible to do it all in one combo. Just remember when it locks, it's not counted.
Once you light the time drive and do a time machine frenzy, I like to have super warp lit on the left award ramp. Active super warp as your ball saver starts to run out for extra time and huge points. Hitting the jackpots and collecting the fragment unlocks Ancient Rome.
Once in the Distant future, do the explorations for more big points, if you've been doing quick shot you can probably get all the awards and then do a ramp rampage for extra points. Activative the time drive, then travel to Ancient Rome and do the explorations there.
I'm not sure how to activate the Prehistoric Times, probably through doing everything you've already been doing. You can travel there next and do more explorations for even more points.
Eventually I believe it's actually possible to complete the pinball machine (where you get to do a ten ball time machine frenzy I think) but I've never actually done that. Just read it in the manual when I had an actual copy of the game.
Extra tips: Hitting the ball target things in the top right cycles through the continents. To start an exploration, hit the left ramp that the ball originally goes through when you start a game, and try aim for roughly 3/4 of the way down the flipper to get it. You can even hit the crystal from here. Multipliers get you good points. Cycle through the two x's with the flippers to boost them. Eventually this will get you an extra ball so it's worth it.
Hitting the flippers will cycle through the S C A N letters. Try get scan as often as possible to get a superscan. Superscans can unlock some useful stuff.
Press space bar to tilt the machine when you think you're in danger, but don't overdo it. It can seriously backfire on you, so use it in an emergency.
Getting below fifty million on the third ball lights video mode. If you're getting below fifty million on the third ball though, you're playing badly. This isn't how you get the big points.
Hit the drop targets to advance awards and quick shot.

If I can get my screen capturing software working, I'll upload a few videos of what I can do with the game. I've had an actual copy and been a fan of the game ever since it was released and forgot about it for years, until GOG came along.
Ahh, I see. A little precognition is useful here. I must admit, I miss it very often, especially if the ball is going quite fast. Once you've had the ball fall down the right gutter tons of times you eventually get a little bit of a sense for when it might be heading that way, so the best time is to grab it BEFORE it falls. You can save it after, but you don't have that much leeway. So it's best used as a preventative measure. Unfortunately if you time it badly and the ball is spinning wrongly, it can inadvertently send the ball down the right gutter, even if it would normally be safe. You can also use it if you think it's going to miss the pin and fall down the centre, but that's also quite risky and requires split second thinking if it's going to miss the flipper or not.
The left gutter of course is protected by the 'lucky' function. Although it's seemingly random, you can tilt the pinball machine to force a 'lucky', but it's far from fool proof.

How do you get even the third level of video-mode then? I regularily beat the first two levels perfectly (doing so awards an extra ball) and the mode always ends there. Are you sure there really are three, even four levels? I can't see anything that indicates there are more than two.

There are two ways to do it.
Firstly, the easy way: let two balls go through so you are below 50 million. This lights video mode and lets you do the first two levels. Next, light the awards and get video mode. This will take you to level 3, provided you have perfected levels 1 and 2. If not, it will take you to level 2. Once you have completed level 3, I believe it takes you to level 4 (I'll go test it out in a bit, but I'm almost certain there is a level 4, I just don't do video mode too much).
Secondly, play normally, but keep lighting scanner as much as possible. Get video mode through awards, then pray that you get a superscanner (or normal scanner) that awards a video mode.
I've attached proof of level 3. :P

Allright, thanks. I guess I just haven't managed to beat one then another in the same game yet then.