(Link to video)
Alex Kidd was an unofficial mascot for Sega in the late 1980s. The Lost Stars is the second game in the Alex Kidd series. It was originally released as an arcade game in 1986 and ported to the Sega Master System in 1988. Lost Stars is a simple platformer on the surface but ended up being a surprisingly complicated TAS to optimize.
Each level contains some powerups that are either visible or hidden. The hidden powerups can be uncovered by jumping over their location (requires slowing down to collect) or shooting the location. The S powerup gives Alex the ability to shoot enemies, there is limited ammunition but this is almost always not an issue. The J powerup gives Alex the ability to jump higher but sometimes it’s not useful since it can make him jump too high. The SC powerup gives you more health/time. This is always avoided to reduce time spent on score screens.
After beating the first seven levels, they repeat but with harder enemy layouts. While this seems repetitive, sometimes different strategies are used due to different powerups being available.

Tricks and Techniques

Lag reduction is extremely important in this game. I wrote a lua script that calculates velocity based on position so that I could pick up some undetected lag frames. By jumping on different frames, the game has different amounts of lag. Often, this meant testing every possible frame to jump. Jumping is almost always less laggy than walking. Alex shoots projectiles in this game, which cause lag. Balancing the lag from the projectile on screen with the lag from the enemy on screen is difficult. Often every frame for shooting had to be tested.
Alex will jump the same height regardless of how long the button is held for. This means that managing jump spacing and deciding whether or not to get the J powerup is essential. In some rare cases, holding jump for longer reduces lag.
Speed conservation is extremely important. If you have to slow down at all you are forced to slow down to roughly half of the max speed. It takes 63 frames to reach max speed again after slowing down. Slowing down loses 15-16 frames. The method to slow down that loses the least time is to swap from holding L+R to R or R to L+R depending on what was already held.
It’s possible to clip some objects by holding left+right. If you start the level holding L+R you will not lose any speed, but swapping from R to L+R will lose 15-16 frames. This becomes particularly difficult when levels involve clipping and shooting enemies since, you have to slow down to swap between L+R for clipping and R for shooting. When holding L+R Alex will walk forwards but jump and shoot backwards.

Useful Addresses

0x0304Y Position
0x0303Fine Y Position
0x0307X Position
0x0306Fine X Position
0x0D1DHealth
0x0D1CFine Health
0x0D16Jump Height
0x004EScreen X (1)
0x0050Screen X (2)
0x004FScreen X (3)

Level Comments

In level 1 there were a few enemies that were unavoidable without slowing down. Having the jump power up is best as a deck of cards is unavoidable at full speed without it. Underneath the train tracks I run into a wall. This looks like a mistake but it’s faster than slowing down before the wall. I was able to jump through the bouncing ball enemy by shooting the ball before jumping through, I don’t fully understand why this works. Level 8 follows a similar strategy but with more slowing down for enemies.
Level 2 is the first instance of L+R clipping. Luckily I can keep holding L+R since there are no enemies to shoot. On the green swinging thing I jump, regrab it then jump again. This allows me to jump off earlier and land on the platform to make it over the wall. There is also a small section of platforms which move left and right. I scroll the screen far enough to load the platform then stop moving right since moving right the whole way would make me overshoot the platform. I die at the end of this level to save time. It's possible to get some very different death animations so I had to manipulate a quick one. Level 9 is a similar route, but I have to use a precise shot to kill a robot to the right/underneath me by shooting to the left.
In level 3 I uncover a hidden jump powerup which saves considerable time. It should be quicker to shoot the powerup rather than slow down for it, but I lost more time due to lag with that method.
In the water levels (Level 4 and 11) Alex’s height doesn’t affect lag. This means that only my shot timing needed optimization. Regardless, this was one of the hardest levels to optimize. Level 11 had the additional challenge of managing limited ammunition.
In Level 5 I was able to use the jump powerup to land on the top of the cave rather than going through it. This saved roughly 50 frames over going through the cave. A disadvantage was that I needed to slow down before hitting the balloon. The balloon keeps a speed associated to the speed at which you grabbed it, so it is very important to be at the highest speed possible when grabbing the balloon. In Level 12 I had to go through the cave as there are no jump powerups. In both levels I had no jump powerup for the hanging thing leading into the mouth after the balloon. Having jump there would have saved time as I could leave the hanging thing earlier.
Level 6 had a lot of management with L+R clipping and holding R to shoot. I start the level with L+R and clip, then I use the slowdown from swapping from L+R to R to grab the jump powerup. Without the jump powerup I couldn’t make it through the second red ball with the invincibility frames. Level 13 was a lot harder since there was no jump powerup and more enemies.
Level 7 has a feature where Alex jumps extremely high (higher than the jump powerup). While this seems to help, sometimes it can cause problems. I use a glitch on the moving platforms where I jump into a platform but only hold the jump button for just long enough to start the jump. This causes Alex to enter the walking animation but keep the arc from the jump with a little bit of extra distance. This distance was just enough to hit the bouncy thing and make it over the ice spike without slowing down.

feos: Compared to the other 2 SMS Alex Kidd games we have published, this one is incredibly simplistic. You just run'n'jump the entire time. And while those other games have runs that are fairly short, which helps to keep their action density concentrated, this one has less levels, but it repeats them twice, resulting in a final time that's longer than what those 2 have combined. So since it's so much simpler and longer, accepting to Vault.
To publisher: Don't forget the overscan.
Spikestuff: Series of Publishings going on now.

TASVideoAgent
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This topic is for the purpose of discussing #5365: The8bitbeast's SMS Alex Kidd: The Lost Stars in 20:17.28
mklip2001
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Nice submission. I admit, though, that I was more excited when I saw it was an Alex Kidd game than when I actually watched the run. This feels less like Alex Kidd (especially with no rock-paper-scissors matches) and more like a bad version of Adventure Island with screeches of "Aaaahh!" and "Find the missing ball!" And why is there a space area called "Ziggurat" with no ziggurats and some random Statue of Liberty? It's a real shame the game needed as much trial and error as you say largely just to manage lag. I don't know if the end result was really all that interesting. I actually found the water stages to be the best with more freedom of motion and more "shoot anything that moves" attitude. The game grew on me a bit more in the second half, but ultimately I think this counts as another run-right-for-justice generic platformer. I have to vote No: it was a good run, but I was not really entertained enough.
Used to be a frequent submissions commenter. My new computer has had some issues running emulators, so I've been here more sporadically. Still haven't gotten around to actually TASing yet... I was going to improve Kid Dracula for GB. It seems I was beaten to it, though, with a recent awesome run by Hetfield90 and StarvinStruthers. (http://tasvideos.org/2928M.html.) Thanks to goofydylan8 for running Gargoyle's Quest 2 because I mentioned the game! (http://tasvideos.org/2001M.html) Thanks to feos and MESHUGGAH for taking up runs of Duck Tales 2 because of my old signature! Thanks also to Samsara for finishing a Treasure Master run. From the submission comments:
Shoutouts and thanks to mklip2001 for arguably being the nicest and most supportive person on the forums.
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I'm a big fan to sega games and after alex kid in miracle world they have killing alex with poor games like this!!! Holy shit colors, bad sprite and repetitive background (the space level is a joke!!)...I'm happy you have save alex's honor with this Tas. YES vote
GAW sms... Totally destroyed
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Liked the submission notes, hated the jump sound. Voted Meh.
Warning: When making decisions, I try to collect as much data as possible before actually deciding. I try to abstract away and see the principles behind real world events and people's opinions. I try to generalize them and turn into something clear and reusable. I hate depending on unpredictable and having to make lottery guesses. Any problem can be solved by systems thinking and acting.
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. ---- [3329] SMS Alex Kidd: The Lost Stars by The8bitbeast in 20:17.28
PCachu
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Obviously they misnamed the game. In keeping with the series theme, it should be Alex Kidd in NO INDOOR VOICE WORLD.
Post subject: Find the magic ball!
Zucca
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I completed this game as a kid back in early 90's. I remember this game being somewhat strange, and, oh boy, it still is. Even stranger now. Those naked, chubby, guys... WTH... Your only real enemy in this game is time. I've always hated games like that. But being a Alex Kidd game I had to play it back then. And what's the plot in this game? It has something to do with the star signs... Well. It's a "lost stars" after all. I wonder if it's the same guy who did music on this game as well as for Fantasy Zone... The style of the music in some levels are quite similiar. Anyway. The TAS. I have to give "meh". And that's only because the repeat of the (almost) same stages twice. So it's more game's fault than anything else.
trazz wrote:
Killing the skeletons sooner or letting the skeletons live (unlive?) won't affect that at all.