Spy Defense (Compute's Gazette)

If shoot-'em-up arcade games are you weakness, this exciting action game will provide you with a challenge that will make you come back again and again.
Fighting aliens is a dangerous job, as we've all seen in the movies. For some reason, aliens always have an incredible variety of weapons at their disposal: death rays, regenerating tails that detach to soar like rockets toward their enemies; or perhaps toxic, sulfuric breath. It's a wonder the humans ever win. But this time, we have your, the official Spy Defender, to help humankind.
The article for this game can be found on page 24 of Compute's Gazette Issue 58 (April 1988)

Why TAS This Game?

The continuation of TASing games from my all-time favorite magazine, Compute's Gazette. This makes my 39th TAS from this series.
Here is another one that I never typed in. I deeply regret not ever having this magazine. It turned out to be one of the greats. Now, I'm so glad that I have gotten to experience this one...as it is truly a classic shooter with extras that separate it in a unique category.
Previous Compute's Gazette submissions include (In order of submission):
1Astro-Panic!2Royal Rescue
3Miami Ice4Chopper 1
5Spike6Heat Seeker
7Omicron8Alien Armada
9Star Dragon10White Water
11Space Gallery12Bagdad
13Race Ace14Quolerus
15Trap16Maze-Mania
17Balloon Blitz18Bowling Champ
19Circuits20Going Up?
21Space Dock22Saloon Shootout
23Sno-Cat24Queens' Quarrel
25Stronghold26Lincoln Green
27Disc Blitz28SuperSprite
29Dunk30Basketball Sam & Ed
31Bee Zone32Q-Bird
33Space Worms34Powerball
35Castle Dungeon36Pool
37Snake Pit38RADs

Game Difficulty and Ending

This game doesn't have a difficulty setting, but it can be classified as complete upon finishing the 8 the level...as it doesn't increase in difficulty or demonstrate any new content afterwards. This information can be verified in the article text on page 25. At the completion of Pit 8, a congratulation screen is presented.

Effort In TASing

The idea of optimization is certainly a different animal in this game. Below are some key details about my efforts:
  • RNG: This game doesn't have RNG, in a normal sense. Its one of those variables where movement and the de-spawning of enemies can change where and when more enemies will spawn.
  • Each level, has a different holding capacity of "Pieces" used to build the bridge. During the creation of this bridge, it is helpful to force the "Black" satellite to spawn on a side that helps to collect it quickly. That way, you can continue to drop more pieces...without delay. If you own a number of pieces that can complete the bridge, you must race to the bottom so that you can get the "Spy" to start walking across quickly. While getting this refill of pieces, you must continue shooting enemies so that the "Black" satellite will spawn faster. Because you have to wait for it, you can remain up higher to battle the enemies until the last few pieces can be filled in.
  • Getting multiple enemies to spawn in the same location. Doing so, speeds up the process of getting the "Black" satellite faster.
  • The last "Pit". Once you have filled in all the bridge pieces, there is no reason to continue with inputs. So after that last piece has dropped...the inputs are finished. This cuts a large number of seconds...as it coasts to the end where a congratulation screen is given.

Human Comparison

Here is another comparison video of an 8-bit community member, NebulusLabyrinth79.

UPDATE

Initially, after I (DrD2k9) figured out a way to improve the first stage (through a combination of strategy change and RNG manipulation), we thought it would be easy, quick, and worthwhile to redo the run. It was definitely worthwhile, but quick and easy it was not. After a few months of work, we've finally completed the redo of the run. Below is a breakdown of the changes from the original submission to the current version. Frame Numbers are based on the first bridge piece drop of the stage.
PIT # OLD FRAME NEW FRAME DIFFERENCE FRAMES SAVED/LOST
1 922 922 0 96
2 2077 1981 96 72
3 2948 2780 168 78
4 3930 3684 246 219
5 5040 4575 465 -50
6 6235 5820 415 148
7 7546 6983 563 173
8 8877 8141 736 92
Final Input 9354 8526 828
Total Savings 828 frames
As can be seen, on most stages we gained a significant number of frames, but on Pit 5 we lost 50 frames compared to the original. We both tried multiple times to improve Pit 5 further, but we were simply unable to do so. We aren't happy with the loss, but are satisfied with the overall improvement through the run (and frankly we're sick of looking at this game).
This brings up randomization. RNG can be manipulated by altering inputs of both the active player (Joystick Port 2) and of the inactive player (Joystick port 1). This was heavily used to control enemy and satellite spawn points. Unfortunately, the highly variable RNG also makes it impossible to determine if a round is truly optimal or not.
Because of the nature of the RNG, I fully believe this run may be improvable. However, a change at any point in the run would necessitate completely redoing everything thereafter. And as we saw with Pit 5 above, the subsequent RNG may actually make some stages slower.
All that said, I'm satisfied with the run as it stands.

DrD2k9: Claiming for judging.
DrD2k9: Delaying as nymx and I rework this due to new tech.
DrD2k9: Updating the movie file. Updating the embedded encode. Setting status to NEW for a different judge to take.

feos: Claiming for judging.
feos: Accepting
fsvgm777: Processing.


TASVideoAgent
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This topic is for the purpose of discussing #8649: nymx & DrD2k9's C64 Spy Defense in 02:22.53
nymx
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I'm not surprised at this, but DrD2k9 has found ways to improve this TAS. His ideas have surprised me, as this game isn't exactly straight forward. Also, this game presents some odd behavior that nether of us have answers to. As with all my TASes, I don't want to leave anything behind. So we will be trying to figure this out. He will be added to this submission as a co-author, since he has found 147 frames. So we are going to collaborate through another run-through.
I recently discovered that if you haven't reached a level of frustration with TASing any game, then you haven't done your due diligence. ---- SOYZA: Are you playing a game? NYMX: I'm not playing a game, I'm TASing. SOYZA: Oh...so its not a game...Its for real? ---- Anybody got a Quantum computer I can borrow for 20 minutes? Nevermind...eien's 64 core machine will do. :) ---- BOTing will be the end of all games. --NYMX
nymx
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Alright, I have been reviewing the findings from DrD2k9 and I'm surprised that this game has mechanics that are more exploitable than I originally thought. Now that I understand what he found, I was able to further the improvements on the first Stage by 8 frames. At this point, I'm beginning to see some tricks that allow me to make this kind of optimization possible. I will try and commit to 1 stage a day. This means it will be ready in just over a week.
I recently discovered that if you haven't reached a level of frustration with TASing any game, then you haven't done your due diligence. ---- SOYZA: Are you playing a game? NYMX: I'm not playing a game, I'm TASing. SOYZA: Oh...so its not a game...Its for real? ---- Anybody got a Quantum computer I can borrow for 20 minutes? Nevermind...eien's 64 core machine will do. :) ---- BOTing will be the end of all games. --NYMX
nymx
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Joined: 11/14/2014
Posts: 927
Location: South Pole, True Land Down Under
I figured to give an update on the progress here. Life...need a say more? Just about halfway through this re-work, and we are looking at 300+ frames cut so far. The discoveries from DrD2k9 are not easily implemented, but are certainly worth the effort.
I recently discovered that if you haven't reached a level of frustration with TASing any game, then you haven't done your due diligence. ---- SOYZA: Are you playing a game? NYMX: I'm not playing a game, I'm TASing. SOYZA: Oh...so its not a game...Its for real? ---- Anybody got a Quantum computer I can borrow for 20 minutes? Nevermind...eien's 64 core machine will do. :) ---- BOTing will be the end of all games. --NYMX
nymx
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Joined: 11/14/2014
Posts: 927
Location: South Pole, True Land Down Under
Just letting everybody know, we are getting close to being done. This has been a hard strategy to implement, but it is worth the effort.
I recently discovered that if you haven't reached a level of frustration with TASing any game, then you haven't done your due diligence. ---- SOYZA: Are you playing a game? NYMX: I'm not playing a game, I'm TASing. SOYZA: Oh...so its not a game...Its for real? ---- Anybody got a Quantum computer I can borrow for 20 minutes? Nevermind...eien's 64 core machine will do. :) ---- BOTing will be the end of all games. --NYMX
nymx
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Editor, Judge, Expert player (2227)
Joined: 11/14/2014
Posts: 927
Location: South Pole, True Land Down Under
Well, it was a hard road...but we are finished. The kind of optimization here was hard to come by, but DrD2k9 figured out a trick that surpassed my understanding of this game. He was the bread winner of this optimization. With 828 frames cut, I congratulate you for figuring this out.
I recently discovered that if you haven't reached a level of frustration with TASing any game, then you haven't done your due diligence. ---- SOYZA: Are you playing a game? NYMX: I'm not playing a game, I'm TASing. SOYZA: Oh...so its not a game...Its for real? ---- Anybody got a Quantum computer I can borrow for 20 minutes? Nevermind...eien's 64 core machine will do. :) ---- BOTing will be the end of all games. --NYMX
Post subject: Movie published
TASVideoAgent
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This movie has been published. The posts before this message apply to the submission, and posts after this message apply to the published movie. ---- [5777] C64 Spy Defense by nymx & DrD2k9 in 02:22.53