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Intelligentleman

Shark! Shark! Orbit Theory

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Just got done with a round of Shark! Shark! after several months of not playing rounds of Shark! Shark! Approaching 50k points, I started to have this thought in the back of my mind that the titular shark was locked into orbit with my fish. As my score progressed, that "orbit" seemed to get progressively tighter, faster to a point where the shark was almost comically omnipresent and infuriatingly agile.

 

 

16840C59-FB08-41D4-8CCC-F0ECB40FCAB0.jpeg

Edited by Intelligentleman

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Difficulty increases at specific score points.  Probably at 50k, then at 90k and 100k.  The shark gets more aggressive.

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3 hours ago, mr_me said:

Difficulty increases at specific score points.  Probably at 50k, then at 90k and 100k.  The shark gets more aggressive.

I know when I hit 90k the game becomes almost impossible for me!

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18 minutes ago, wolfy62 said:

I know when I hit 90k the game becomes almost impossible for me!

Yeah. And in my mind I just imagine the shark making tighter and tighter circles around my fish.

 

Honestly the first half of the game, it's the Shark who is the prey. I am the boss of that fish until 50k after least.

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I wish we could see where the shark goes when it leaves the screen. It either goes no where, or the playfield extends beyond the boundary of the screen and the shark continues its routine off screen.

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3 hours ago, Intelligentleman said:

I wish we could see where the shark goes when it leaves the screen. It either goes no where, or the playfield extends beyond the boundary of the screen and the shark continues its routine off screen.

Captain Quint is just off screen trying to capture it...

Crackers Quint GIF

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Once the shark gets too fast, then I don't bother with it.  I'll take a bite and it would usually flee, so Iif I survive then I let it go.

 

I like to get the lobster and crab at the bottom. 

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2 hours ago, JasonlikesINTV said:

Ah, a fellow man of class, I see 🍷🦞

Gents. I have just come to this. It's a thousand points plus an extra fish. But I like to use the shark to advance my score... At least until the point where it's got super powers.

Edited by Intelligentleman
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Actually, this is a game I recently reverse-engineered and I had seen the part of the ROM where the difficulty increases.

Spoiler
  • 5,000
  • 15,000
  • 25,000
  • 50,000
  • 90,000
  • 100,000
  • 250,000

There are two memory values pertaining to difficulty.  The first one has to do with the shark's speed.  The second one has to do with how often the shark changes direction.

Spoiler

$171 for the speed, and $175 for the direction updates.

 

Looks like $171 maxes out at 90k, and $175 is set to 10 at 100k and 25 at 250k.

Poking the value 25 ($19) in the "direction update" address turns the shark into the guided missile from Astrosmash.  With the shark speed still to minimum at the beginning of the game, it's actually kind of fun playing with that little rule change.  Maybe I should tweak the hack some more.

Edited by Zendocon
Clarification
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1 hour ago, Zendocon said:

Actually, this is a game I recently reverse-engineered and I had seen the part of the ROM where the difficulty increases.

  Reveal hidden contents
  • 5,000
  • 15,000
  • 25,000
  • 50,000
  • 90,000
  • 100,000
  • 250,000

There are two memory values pertaining to difficulty.  The first one has to do with the shark's speed.  The second one has to do with how often the shark changes direction.

  Reveal hidden contents

$171 for the speed, and $175 for the direction updates.

 

Looks like $171 maxes out at 90k, and $175 is set to 10 at 100k and 25 at 250k.

Poking the value 25 ($19) in the "direction update" address turns the shark into the guided missile from Astrosmash.  With the shark speed still to minimum at the beginning of the game, it's actually kind of fun playing with that little rule change.  Maybe I should tweak the hack some more.

Do these values nessecarily advance at the same rate? Meaning, is it possible to have a fast shark that doesn't turn as fast. Or a shark that moves slowly, but can change directions on a dime?

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I just looked again at the ROM disassembly.

Spoiler
  • First, the game clears R2 and R3 (sets their values to 0).
  • Then, it checks for each of the above-mentioned values up to and including 90k (there are two separate 16-bit values used foreach player's score: one for thousands of points, and another for the bottom 3 digits).  Every time the current score exceeds that threshold, R2 is incremeneted.
  • At 100k and 250k, the literal values 10 and 25, respectively, are written to R3.
  • Before writing R2 to $171 and R3 to $175, there's a check to see if there's already a higher value at those memory addresses.  That's what I didn't notice before.

Moral of the story: something else might be affecting the difficulty, besides score thresholds.  I say "might be" because perhaps it's looking at the current score of one player, who's trailing behind the other player, in which case the difficulty is being made not to fluctuate.  It might be the case that the shark becomes more aggressive every time you kill it, so I'll keep poking around.

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14 minutes ago, Zendocon said:

I just looked again at the ROM disassembly.

  Reveal hidden contents
  • First, the game clears R2 and R3 (sets their values to 0).
  • Then, it checks for each of the above-mentioned values up to and including 90k (there are two separate 16-bit values used foreach player's score: one for thousands of points, and another for the bottom 3 digits).  Every time the current score exceeds that threshold, R2 is incremeneted.
  • At 100k and 250k, the literal values 10 and 25, respectively, are written to R3.
  • Before writing R2 to $171 and R3 to $175, there's a check to see if there's already a higher value at those memory addresses.  That's what I didn't notice before.

Moral of the story: something else might be affecting the difficulty, besides score thresholds.  I say "might be" because perhaps it's looking at the current score of one player, who's trailing behind the other player, in which case the difficulty is being made not to fluctuate.  It might be the case that the shark becomes more aggressive every time you kill it, so I'll keep poking around.

This would be amazing. So on the one hand, you could DESTROY the shark for the first 15 or so minutes of your game. This is going to give you a fast track to a good score and a horde of extra lives. BUT, the consequence of that is that from this point forward you now have to deal with an increasingly homicidal shark.

On the flip side, you could vow to evade the shark, focusing on eating fish and crabs and lobsters. It might take longer, but the shark will remain docile for longer.

Edited by Intelligentleman
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That's my guess right now.  I always thought it was lame to just focus on killing the shark and amassing a ton of extra lives, when it would be more realistic to eat smaller fish and grow in size until you're big enough to even consider trolling a shark.  If I find something else writing to either of those two values, I'll let you know.

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Sir (Intelligentleman) this is something of the best (your hacking in general), because i haven't visited this forum since at least two years.

 

---

 

"Moonsweeper" ts...

 

 

electricdog.jpg

Edited by Gernot

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On 5/1/2021 at 3:26 PM, fdr4prez said:

I like to get the lobster and crab at the bottom. 

 

How do you get the lobster and crab?   Any way to take out the jellyfish also?

 

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10 hours ago, doctorclu said:

 

How do you get the lobster and crab?   Any way to take out the jellyfish also?

 

Hang out at the bottom and eat them while they are dropping back downward. Big points and an extra life. 

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8 hours ago, IntyFanMatt said:

Hang out at the bottom and eat them while they are dropping back downward. Big points and an extra life. 

Now that is awesome.   How about the jelly fish?

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25 minutes ago, doctorclu said:

Now that is awesome.   How about the jelly fish?

Jelly fish are indestructible, don’t ya know?  Lol. 

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On 6/1/2021 at 2:37 AM, doctorclu said:

Now that is awesome.   How about the jelly fish?

RTFM (cough)

Guiding a shark into a jellyfish won't give you points but you got rid of at least one.

The manual tells you: "let the sharks take care of them".

 

But i suspect you know it you just liked to hear if someone is stupid enough to fall for your trap, in other terms if the dudes themselves really read the manual.

If not then pardon me for my assumption.

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