Submission #7962: The8bitbeast's SMS Fantasy Zone "demo glitch" in 03:16.82

Fantasy Zone is a side scrolling shooter released for the Master System in 1986. Unlike many shooters, Fantasy Zone gives you full movement of your character without locking you into autoscrolling – making it a fun fast paced speedgame.

This TAS uses a demo desync glitch to skip the majority of the game apart from the last level and the boss rush at the end of the game. The glitch skips a large portion of the normal game, but the remaining section contains a lot of glitchless gameplay, routing and optimisation. Especially since the demo glitch leaves you with virtually no money to buy upgrades, forcing money routing and optimisation to play a much larger role than a glitchless run.

This glitch is the fastest known way to complete the game, leading to a completion time of 3:16.820

Each demo in the game starts with Opa Opa flying right for a short time, then breaks off into some chaotic movement afterwards. The game will autofire the shoot button during this time and pick a different random direction for Opa Opa roughly every 16 frames. Given that the direction is random, it can be manipulated by doing different things before the demo or using the pause button in the demo.

If the demo dies, you get kicked back out to the title screen – and this is very common. However, if you’re very lucky and the demo beats the level, then you will take over on that level fighting the boss as normal and then progress with the normal game from that point. By skipping the demos up to level 7 (the last level), I can manipulate the demo to beat the level and start me from the level 7 boss. After this, there is only the boss rush left and then the game is complete.

In terms of manipulating the demo, I can use pause presses to change the d-pad directions pressed in the demo. Since its about 16 frames between the demo changing directions, that gives me 8 pause presses for potential manipulation. Due to the way the RNG works, many of these cause no change in the direction moved. So realistically, each update I can choose between 2-3 directions for Opa Opa to move based on the RNG unless I go back and insert more pauses earlier (which would ruin previous direction manipulation).

The demo can press L+R at the same time or U+D at the same time (or all 4). In these cases, left is prioritised over right and up is prioritised over down. For this reason I opt to go left through the level, as the game has a 50% chance to move left but only a 25% chance to go right (and a 25% chance to enter no input, causing the same direction as before to continue).

Since up takes priority over down, I also have to manipulate a lot more down presses than what would naturally happen.

The level completes when I destroy all the bases. If I went straight for the base in the demo, I would likely hit it and die before doing enough damage to destroy it, so I often need to turn back to the right and come back a second time to fully destroy it.

I did not find this glitch as it was documented on the TASvideos forums in 2009: https://tasvideos.org/Forum/Topics/8392 Since reading about this glitch I have always wanted to TAS this game, but was always too intimidated about the RNG manipulation in the demo until now.

In the forum discussing the glitch, CoolKirby2000 posted a demonstration TAS using it https://youtu.be/x_oUh2uwPc0 This TAS was made by Tee-N-Tee and CoolKirby had encoded it. I won’t compare to this TAS in detail, as it was only meant to be a demonstration TAS and not optimised for time, but I did ensure to match or beat each section in the TAS, primarily thanks to upgrade routing and demo optimisation. This TAS saved about 40 seconds over this demonstration video.

Any money collected during level 7 (the demo) doesn’t count. Luckily if you have money before entering the demo it will stay. So I collect $1,100 from the first level and then do the demo glitch. I could have a lot of money by doing the demo glitch on level 6 then playing level 7 normally but that would be slower.

The possible upgrades are shown below. The prices keep increasing for each of the same item you purchase.

Note: The gun upgrades last forever if you buy all the boosting upgrades.

There is a lot of choice in the routing. My first instinct was to collect no money and go in without upgrades. This doesn’t work as the last boss can kill you very quickly if you wont have upgrades and it’s nearly impossible to beat it without upgrades. Upgrades also save some cycles one earlier bosses in the boss rush.

The staple in many Fantasy Zone runs is to use the heavy bomb as this can 1 hit kill many threatening bosses. However, at 1000+ per bomb I would need to spend several seconds grinding for each one I want. It also locks you into using them, so you can’t stack it with another bomb upgrade.

Very surprisingly, the twin bombs were the best choice I found for this run. Although they don’t increase your DPS by much, they do by a bit and permanently just for $100. This slightly speeds up all bosses, but more importantly makes some other bosses cut a cycle. For example it allows me to kill the fish boss in one cycle rather than two, which would normally be impossible due to the gun upgrade running out just before it (unless I bought heavy bombs). The most important part was the last boss, which I was just able to kill quickly with the twin bomb. This saved me from needing heavy bombs at all.

Twin bombs locked me out of any other bomb upgrades, so my only other choice was boosters or gun upgrades. The boosters weren’t worth it was you don’t do much travel in the boss rush, but I did opt to get the wide beam gun upgrade. This just does 2x the damage of the normal shot and runs out after 15 seconds, but it still speeds up many bosses, like the lab boss which I can kill from inside just a frame before the hurtbox spawns.

Although the boss rush could have been faster with more money and several heavy bombs, I’m pretty confident that I found the best solution which trades off money collection for speed. Compared to the route used in the demonstration video which was $3000 and 100 seconds, this route is cheaper at $1,100 and only 80 seconds for the boss rush.

There was a v1.0 Japanese version but it doesn't have a reset button as it defaults to the J BIOS. Given the reset button speeds up the demo glitch a lot, I opted to use the US version.

Many of the optimisation concepts are similar to my TAS of the NES version, so I will not repeat them here: https://tasvideos.org/6625S

The boss strategies are as expected. Mash shooting and bombs in combination as fast as possible when the boss is vulnerable. You can sometimes increase your shooting hits per second by starting shooting from further away and moving closer after firing the first shot. This allows you to squeeze in a few more hits in a given vulnerability window (works a bit like the Doppler Effect). However, this didn’t seem to work out on the Master System version as well as it did on the NES version (maybe because of the lack of speed boost upgrade?)

Bombs will go further if you’re moving, so I’ll often do a cheeky right or left press to shoot them further in the boss fights.

The moon boss has a health bar for each shooter and I can hit multiple at once with the wide beam.

The turtle boss has RNG with how long its head stays out for. I managed to get it almost killed in one cycle with 11 hp left, but couldn’t find any other RNG which had its head out for long enough to kill. The RNG can be manipulated by your height before the head comes out or the precise timing of when you come into the turtle boss (determined by your last hit on the previous boss).

Another small optimisation came at the end of level 7 (the demo level). Since I gain control as soon as the last base is defeated, I quickly grab all the coins to despawn them from the screen. This makes the boss load in quicker, since it wont load in with objects on screen.

This game has one of the best ending text scrolls ever, especially considering the preceding cartoony fun game:

OPA OPA (THE PLAYER) HAS NOW DESTROYED THE INVADING ARMY AND RESTORED PEACE TO THE “FANTASY ZONE”.

HOWEVER, HE HAS MIXED EMOTIONS BECAUSE HIS LONG LOST FATHER WAS THE CHIEF OF THE ENEMY FORCES.

ONE BURNING QUESTION THAT WILL REMAIN WITH HIM UNTIL HIS DYING DAYS…..” WAS MY VICTORY REALLY WORTH THE PRICE I HAD TO PAY?”

THE END

ThunderAxe31: Claiming for judging.

ThunderAxe31: This movie aims to beat the game as fast as possible, by using a demo glitch. It's a kind of glitch that has also been featured for various other games. In order to distinguish from a non glitched-movie, I've added the branch label "demo glitch".

The level of optimization is impressive. Everything is allright, accepting for publication.

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