Submission #7653: Winslinator's A2600 Jungle Hunt in 04:36.39

(Link to video)
Console Atari 2600 Emulator BizHawk 2.7
Game Version any Frame Count 16562
ROM Filename Jungle Hunt (1982) (Atari) [!].A26 Frame Rate 59.9227510135505
Branch Rerecord Count 25812
PowerOn Authors Winslinator
Game Jungle Hunt
Submitted by 74FalconX on 8/20/2022 2:08:29 PM

Submission Comments
The linked video is not updated and only plays through one loop. The submission was updated to play through 3 loops as done in this userfile.
"The object of Jungle Hunt is to rescue Sir Dashly's kidnapped mate, who, after hours of valiant fighting, was overpowered by two man-eating (and woman-eating) savages. To rescue Lady P., you'll have to make your way past four sets of obstacles: the vines of the Forest, the crocodiles of Reptile River, a landslide of bouncing boulders, and the spears of the two masked cannibals."
Objectives
  • Plays on hardest difficulty
  • Plays through three loops starting at Skill Level 2 (after which there is no further difficulty increases)
  • Genre: Action
Difficulty
The hardest difficulty to start the game at is Skill Level 2 (expert), which was selected here. Apparently, this effectively starts the game at 2nd loop difficulty (meaning this TAS effectively ends play at loop 4 difficulty). From what I can tell, loop 2 start difficulty decreases the loftiness of your jumps in the Deadly Forest and increases the speed of vines, crocs, and boulders compared to loop 1 start difficulty.

Deadly Forest

There are 10 vine jumps you must make to progress. Jumping at the highest point of the vine's sway will give the greatest loft to your jump. The TAS goal is to just keep the screen scrolling as you jump from one vine to the next.
  • Loop 1: I delayed the screen scroll for 4 frames on the 4th vine jump to get the next vine in a better position and manipulate luck on later vines, as the initial sway position and sway speed of each vine is determined randomly.
  • Loop 2: Perfect! Screen does not stop scrolling at any time.
  • Loop 3: Deadly Forest really ramps up in difficulty here. Your jump loft is now reduced to practically nothing, so you must be very smart with vine hops to not lose distance up the vine with each jump. The jump loft is so low that I had to let the screen pause in places to A) line up vine cycles so I wouldn't lose too much height and/or die and B) manipulate vines to have a fast enough sway to keep up with the screen scroll better. The speed and initial positions of the first two vines cannot be manipulated—they always start swaying that slow—and it is a very suboptimal pattern. It is so suboptimal that it is faster to die and respawn higher up the vine, which allow greater risks to be taken later. Despite this section looking suboptimal, I examined it very carefully. I predict the only practical way to improve it would be to program a brute forcer to find a faster solution.

Reptile River

You must stab all 14 crocs to progress. A limited number of sprites can be on screen at once so each croc is stabbed as early as possible to get the next one to spawn ASAP.
  • Loop 1: No frames sacrificed.
  • Loop 2: Crocs move much faster and are separated by 48 frames minimum between spawns instead of 64. At first, it might look like I lost frames letting the 3rd croc go by. However, a rogue croc only spawns once both Main RAM address 0x64 reaches a value of 0 and there are no other crocs on screen. Address 0x64 counts down from 48 by 1 unit every frame. When I stab the 4th croc at the earliest possible time, 0x64 reads a value of 27, the 3rd croc disappears at a value of 13, and the 1st rogue croc appears just after a value of 0.
    • One bizarre fact about this stage is that the 2nd rogue croc is the last place where RNG manipulation can be performed for Cannibal Camp in single-frame increments. Stabbing the 2nd rogue croc 5 frames later than earliest ensured the largest time save on Cannibal Camp.
  • Loop 3: I was able to stab all the crocs this time, and although the 2nd croc was stabbed late, no frames were lost once again. The 2nd rogue croc was stabbed 2 frames later than earliest to ensure the largest time save on Cannibal Camp.

Boulder Field

You must bypass 17 boulders to progress by ducking under or jumping over each. I try to keep Sir Dashley running as far to the left as possible because if you lag behind for too long, the screen scrolling will slow down and you'll lose time! Briefly ducking will not lose time. I don't ever duck for more than 5 frames at a time which in no instance was long enough to lose frames. This opens up limited opportunities for entertainment, where I show off ducking under a small boulder in the 3rd loop!

Cannibal Camp

On this stage, jumping has significantly greater horizontal speed than running, so it used when practical. You must jump over 2 cannibals and then you can rescue Lady P. You could just run and jump as fast as you can over each. However, the next cannibal (or Lady P.) will not load until the previous one is off-screen. Therefore, we should start scrolling the screen left when the cannibals are as far to the right as possible (the cannibals will not jump again if the screen is scrolling). By timing my jumps such that I am barely to the right of the cannibals when they decide to jump again, they will be lured to the right and scrolled off-screen fast.
As mentioned earlier, RNG must be manipulated all the way back in Reptile River for different RNG on Cannibal Camp, specifically the duration between cannibal jumps. Basically, the quicker the cannibals can be manipulated to initiate their first three hops, the more frames you will save.
Frames were also saved by jumping right before the game freezes your controls and zooms you to the right when bringing the next cannibal or lady P on the screen. You will regain control about one sprite's length from the right margin instead of at the right margin.
I try to get fancier in the way I beat the stage with each loop to keep up the entertainment value, such as more backwards jumps. None of the goofy movement wastes frames overall.

Samsara: File replaced with a version that goes through 3 loops of the game to maximize difficulty, and judging.
Samsara: Short and sweet little beep-boop game, revolutionary in its bold decision for the player to go left! Such groundbreaking innovation, shown in TAS form, should certainly be rewarded with an acceptance! It also helps that the run is very tightly executed and well-researched, and the submission text explains away the questions I would have had otherwise, but WOW! LEFT!!!

despoa: Processing...

Last Edited by despoa 8 days ago
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