Super Mario BP Oil Spill. Now that was a game that provided me with a good load of fun. And some frustration.
But that's just part of this kind of "platformers" - the decent difficulty.

This post ended up getting pretty exhaustive. Hopefully i can help some people with it and don't just scare all away by this wall of text :P

I kept track of pretty much everything you could count in this game. Which is doable, since this is a simple retro game afterall.

The following table shows all my observations so far. Sorry, the tab characters are missing now unfortunately.

SMBPOS Data Table

Level Time Holes* Mines** Divers Submarines
1-1 80 5 25 0 0
1-2 80 7 20 0 0
1-3 80 8 20 1 0
1-4 80 9 16 1 1
2-1 100 10 16 1 0
2-2 100 12 14 1 0
2-3 100 13 14 2 0
2-4 100 15 12 2 2
3-1 120 15 10 2 0
3-2 120 16 10 3 0
3-3 120 17 10 3 0
3-4 120 17 10 3 2
4-1 120 17 8 4 0
4-2 100? 17 8 4? 0
4-3 100 17 8? 5 0
4-4 100 18 8 5 2
5-1 100 18 6? 5 0
5-2 100 18 6 6 0
5-3 100 18 6? 6 0
5-4 80 18 6? 7 2
6-1 80 19 5? 8 0

*Holes: This does not represent the number of pipe leaks, but the total number of blowfish required to plug all of them.
- Pipe leaks are spawned randomly.
- The biggest single leak requires 4 blowfish to plug.
- The number of fishes seems to increase with the number of holes. Maybe it's also dependant on level, but you sure have a big swarm of them in later levels.

**Mines: This depicts the time periods when a mine is launched from an helicopter. This column contains the most unreliable numbers:
- the helicopters seem to drop them more often while time decreases.
- they are not dropped randomly, every level has prredetermined moments when a helicopter appears.
- every helicopter appears at a random place.

When you look at this data in a table (check this one), you'll notice that the amount of holes, divers and helicopter intervalls seems to follow some exponential formula.

Score list:

Launching Blowfish on...
Mine 0 Points
Living Blowfish 20 Points (both dead or alive)
Diver 100 Points*
Submarine 100 Points (per hit, takes 3 to kill)
Hole 50 (can also be plugged by swimming to the hole)

Further notes...
- Mines that detonate on divers give 100 points (in other cases it won't give points.)
- Bullet Bills killing divers won't give points.
- Plugged holes give 50 points even if the fish swims there itself.

Medal tips:

Getting the medals isn't too hard if you follow the advices of the other tips. However, here are some medal-specfic tips:
*SECRET MEDAL SPOILER*
-The Secret Medal is acquired by waiting about 10 seconds in the intro screen for a polluted whale.
*SPOILER END*
-Glug Glug, Mine your Business, Blow Me: Especially easy if you make a run where you only use your blowfish for one of these and (excluding Blow Me) use up almost all time even if you could already finish the level.
-Sucker, Torpedo Terror: Easy, and even achievable by accident.
-Employee Mercy: You'll also get this one if the emplyees get killed by mines. But you have to grab the blowfish asap in later levels since the divers will kill them otherwise. Try to lure them away from the bottom, and into torpedos in X-4 levels.
-Aquaman: Since 1-ups don't help you in this case, ignore submarines in this run. Aside than that: play careful! For details, check the list below.

General game strategy tips:

- Avoid swimming at the borders or into the oil slick. At the borders the fish might appear and hit you before you are able to notice. While in the middle, you are save from them since the oil leaks to your left and right kill them off entirely.Behind the oil slick might be a hidden mine you forgot about. So handle these areas with care.
- Plug in the border holes at last. This makes everything easier, since the fish will be killed earlier, will less likely be destroyed by BP employees and they might swim into the holes in the last few seconds (while they wouldn't reach the middle).
- Throw your fish not just for attack:
Mario throws the fish notably downwards, which allows you plugging above the sea bottom, especially the middle holes can be aimed to from the borders with all the dead fish floating upwards, which saves an incredible amount of time. Also, if you are just swimming downwards through another dead fish, throw the one you are currently holding to swap them. This is advisable since it pushes the thrown fish down a bit, eventually allowing you to grab it again afterwards. This is more effective yet also a more risky move if you grab the other fish as late as possibly when swimming down at the bottom end.
- Kill the divers asap! Their spears will not only hit you, but also the fish. Swimming right through them is dangerous because they fire their spear constantly if you are three squares within their height, so keep distance without a fish, or you might get cornered by spears.
Swimming up/down in front of them and briskly firing the fish is a good way to kill them. Downwards you can fire the fish a bit above them with quite some distance. You can also try "assaulting" them above a leak with many dead fish once the divers are clustered and near you, just mash the S bottom. You might even be able to reuse these fish.
Luring them into a mine or into torpedoes is also very advisable - the latter is especially effective and easy to do, since a torpedo can kill an entire squadron on the right height at once.
- Once they show up, take the submarines out. Grabbing three fish to blow one is pretty easy, especially if you are lucky and the submarine is above a leak. Just swim right into it, slightly behind the torpedo blasters and throw your fish. Every submarine has about a 50% chance to drop 1-ups.
This leads me to a great tip if you just want to get a good high score...

High Score Tips:

Repeat X-4 levels intentionally! Imho 3-4 or 4-4 are best for this "point farming" trick:

As mentioned above, submarines can drop 1-ups, you might end up getting two lives in one run, resulting in one more life after dieing, and a notably higher score!
Again, try to kill them fast. Otherwise they will dive into the oil slick, making them hardly or even completely unreachable for you.
If you are swift enough you can of course try to kill (some of) the divers at first for some extra 100 points, but this is a risky move and once the submarines appeared, you should kill these first and let their bullet bills do the rest for you.
Of course, only let yourself die once you've plugged all but one hole. At best stay next to it, this assures that you won't "accidentally" finish the level when a fish swims into it. You can in this case, however, kill yourself shortly before, and let the scallywag plug the last hole for the 50 points.

Even if you're just looking for a challenge and try to get as far as possible, i advice killing the submarines at first due to the valuable 1-ups.

One last advice as i end my post here: Don't let this happen to you! O-O