Sunday, 20 May 2018

Uchuu Yusousen Nostromo

A few years back I stumbled across some screenshots of a game for the NEC PC6001 called Nostromo. Since the name of the spaceship from the movie Alien was "Nostromo" it seemed likely it was based roughly on that movie franchise. The goal of the game is to foray into a series of hallways and raid 8 lockers/rooms to retrieve various items while the alien hunts you down. I didn't have a fully operating emulator for the PC6001 back then so pretty much all I had to go by was an animated gift:
Based on that gif I came up with the following rendition of the game. I found the 8 box layout a little boring, so I added a little variety. So I alternated a second style of map. Since I didn't have a clue about the scoring or what the second number meant of the two number at the top left of the screen, I just had the player hit a key when she returned to base in the red area to signal that she was finished collecting.
Fast forward to today and Robert Allen Murphey on the Coco Facebook group mentioned that he was going to take a stab at playing my port. But he used a Japanese title for the game "Uchuu Yusousen Nostromo," which means, I think, "Space Freighter Nostromo." These additional words gave me some additional terms to search for to find out more about the game. I also had been able to get a working PC6001 emulator in the meantime, so I was able to download the game rom image load it up and extract the Basic source code. Although the game is credited to Akira Takiguchi and Masakuni Mitsuhashi on many sites, I noticed that the Basic source code had a set of remarks at the top indicating it was copyrighted by Hiromi Ohba. Here's the link to the original website I found that gave me access to the source code:
Although I was able to load the game into an emulator by James "the Animal" Tamer called "VTrek" (for virtual NEC Trek--the name of the version of the computer unsuccessfully distributed by NEC in North America) either bugs in the emulator or differences between the NEC Trek and the PC6001 wouldn't allow me to run the game. So I had to rely on a video in which a Russian vlogger, Panteryasha, does a walkthrough/review of the game:

Later my son Charlie used some of his computer voodoo skills to download the subtitles of the video and translate them into English, which was really helpful. For one thing, Paneryasha noticed a bug that occurs in higher levels where you are required to collect 7 of each item, but the algorithm that randomly creates the layout of the items in the rooms/boxes (versus blank spaces and purple barriers) can only guarantee a maximum of 6 items for each item type. So you could end up with a screen that it was impossible to clear. However, unlike Panteryasha, I was able to see in the code that there was a possible out. You could let yourself be killed and then hit the "h" key and the screen would be re-drawn with new resources and a time penalty. I changed the 'h' key to "H" and instead of a time penalty I made it so that you lost any points you had accumulated on that screen.

This feature is not just useful for higher levels. Even on lower levels, if you are killed while carrying a load of items, you must then go back out and get at least enough new items for one of the item categories to push your number over the number required for that screen (the second number at the top left). Unless you reach that number the computer will not register that you have collected any items or give you a score for them when you return to the red home base.  However, if you have collected all the items on the screen before returning to your base and are killed, then you will not be able to have those items scored so you can complete the screen. I suspect the programmer added the "H/Help" restart feature to allow you to sacrifice a life in order to continue. The moral of the story is that you must get back to the red base area with at least one category of items at the target number if collected items are to be registered for scoring purposes.

I also replaced with pure Basic all the machine language calls and code in the original that handled player and monster movement. The NEC PC6001's Basic was a little slow, so I suspect that the programmers had to use machine code routines to get speed for the player and monster movement. Luckily the programmer used Basic for all the scoring and screen transitions. I did use a M/L Timer USR function provided by Darren/Mechacoco to handle the countdown timer part of the game, so it should portray accurate seconds. Thanks Darren! And thanks Charlie for translating the comments of the Russian reviewer for me.  Here's what I came up with:
The sound routines were still petty rough.  It took me a while to figure out some of the quirks of how the NEC's SOUND and PLAY commands work. Turns out some of the SOUND commands are just meant to reset the sound chip in various ways and not actually produces noises, so some of the sounds I thought were in the program were not really supposed to be there. I thought I had got a pretty good bug-free version when I noticed a really bad bug. I had never tried shooting at the outside white wall when I was play testing because I knew shooting was for the rooms in the interior, so I didn't notice that you could shoot the exterior wall and escape the screen and have your character POKE into memory areas where you shouldn't be allowed to go. I also added a saved high score feature. This necessitated re-working the main loop a little. Because the original program would simply re-RUN the whole program every time you lost, the programmer didn't care about properly RETURNing from the various main subroutines or resetting variables to zeros, etc. But since I wanted to save the high score from game to game I had to fix these problems. I also noticed that the nearest item type was worth more points (25) than the farthest (10), which seemed odd.  I reversed this order so that risking a longer journey to the left of the screen would be rewarded with higher points. I also changed the original T key layout to be further right on the keyboard, which was more comfortable. And I reduced the time allotted for each screen, as the original amounts seemed excessive:
It has been a long journey getting to a working rendition of this apparently classic Japanese early 8-bit game. It's even, if  Panteryasha is correct, considered one of the first examples of a horror game. This is apparently a result of the cut scenes with the monster and the higher levels when the monster flicks in and out of view, which is kind of creepy and a bit suspenseful. Still, I wonder whether it is true that is the first horror game. I'm aware of at least one game "Alien" for the ZX81 that has similar features, also based on the Alien movie, which might possibly be as early:
Both programs are dated to 1982 by various sources on the Net. I'll let retro-gaming archaeologists figure this out.  In the meantime, I hope some folks might  have some fun playing the MC-10 versions of these classic games.  If you are interested you can now download all my games and the VMC10 emulator by James "the Animal" Tamer from my GameJolt site: There are some instructions there that will help you get whatever program you are interested in running.  Here's a link to a full list of my games: My most recent version of Nostromo is called "NOSTRO.C10".  The older version is called "NOSTROMO.C10".  I have left it there for historical purposes, but I really recommend playing the newer version.

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