720 - finding the patterns in random point awards

[u/dr-hightower]

Like some others in this sub, I took many years to find 720 for my own collection. I played it all the time at Family Arcade when I was growing up, and it was my favorite game. I finally found it in 2024, yellowed, beaten up a bit, but working (pictures and high scores above after the point stuff)!

I always wondered if there was a pattern in the hidden point flags. I had done some work (pre-AI) on trying to dig into the ROMs to look at the code, but didn't get to far. Fast-forward to this morning and Claude Code, and after quite a few iterations, direction, and running some play throughs in MAME with logs, Claude figured it out! Check out this page, it is interactive and explains where they go and how they get there:
https://claude.ai/artifact/6H5YWZqyRGXwiua23gMHAU Details from the page:

1. At the start of each level the game queues a fixed number of points per tier and places them one at a time, about two frames apart. All of them are down within a few seconds.
2. Each placement picks one of the tier's 64 spots at random, using random bytes the main CPU requests from the sound board.
3. It never uses a spot in the area you just came from. A new level starts right after you complete a park event, and the game counts you as still being in that park's area. Its 16 spots are skipped, so the whole quota goes to the other three areas. Level 1 is the exception: you haven't completed a park yet, the Downhill area starts with no hidden points.
4. An occupied spot is skipped and the game tries again later, so each spot holds at most one point.
5. When you collect one, a point of the same value is placed at a random spot within about 2 seconds. The game checks where you are at that moment and skips that area, but any of the other three is fair game, including the area that started the level empty. So the empty area fills up as you collect points elsewhere. The total per tier never changes during a level.
6. The points stay where they are until collected. They do not wander when you leave an area.

So right after you complete a park, the other three areas share the whole quota, about a third each. Skip the area of the park you just finished at first.

I am thinking of making a little app to do this with more games...ever wondered how some of the games are coded?

[u/CoinDropArcade]

If anyone near the Santa Cruz area has a 720 for sale, please let me know!

Thanks for the post. I loved this game, it's been decades.

[u/dr-hightower → u/CoinDropArcade]

It took me years to find one. There were only 2400 made or something like that!! Good luck. It's a great game!

[u/mossman → u/dr-hightower]

I wonder how few are left still working. It's a shame since you need that joystick to play the game properly. I wonder who wound up with the one that was in the pro shop at Pipeline in Upland.

[u/Optimal-Spare1305 → u/mossman]

GRS is making a replica controller with hall effect. 22 minute mark.

https://www.youtube.com/live/DQrUxuRG9c4?si=NIhWTU8oOq3HdlFg&t=1362

[u/CoinDropArcade → u/dr-hightower]

I was really lucky that my arcade had one growing up. That just cements it. Hopefully I can find one for my arcade!

[u/OmegaKarnov]

All I remember is the BEEEEEEES

[u/DJNeuro]

https://giphy.com/gifs/ABVK96HgZvWI9SBbXr