Playing Acornsoft Planetoid in 2017 compared to 1995-1996

On this page:

See also, on separate pages:

defender, what planetoid emulates, mostly acornsoft planetoid and defender
acornsoft defender instructions acornsoft planetoid instructions
Note that the score for a bomber is actually 200 points, not 150 as per the instructions...


In April 2017, having some more time to spend on hobbies I decided to play some games on my BBC micro. I saw's high score competiton tried the current game, Galactic firebird. I got to 27K or so, and others had scored 33k+, but I didn't want to try further as the game just didn't grab me and what I really disliked is the too long pause between dying and playing again, but still I wondered if my skills were now rubbish or that I just needed a bit more practice on that game. Well, to compare then and now, I tried one of my favourites, Planetoid. I could have tried Fortress, at which I got to 268000 and 248000 in 1986, but I am sure that those scores are almost impossible to improve on as I played perfectly for the highest score. I had to even shoot a few barrels of fuel that are hard to get to (behind walls), and for a higher score I would need to shoot a few of the barrels that are almost impossible to get to (also behind walls but closer to them and/or with enemy planes, not sure) because fuel depletes faster each time you go through the course. So Planetoid it was, after not having played it for almost 21 years. My high score in April 1996 was 888150, what would I get to now?

First 3 days:

Tried Galactic Firebird again and got to 33850 which was OK but not great, but I couldn't get myself to put in more effort. So back to Planetoid.

Over the next weeks I played Planetoid from time to time, with my score getting higher, and the realisation of how much high scores depend on subtleties grew (how to not get killed in certain situations, and to make effort to not kill your last man, and in general how to deal with certain situations). It just takes time to master them and to apply them. Also you hit a almost-wall until you get to wave 32, you need to become good enough to reach that (you will get there with about 520k points) and of course have enough lives and smart bombs left over to continue, as at this point the shoot-speed of aliens wraps around making it manageable again, and you can continue. It doesn't get easy as the aliens become faster all the time and suicidally run into you! The swarmers' speed is a problem at high scores and even worse are the baiters/cruisers. Comparing my scores with those from 1995-1996 (I wrote down all my high score improvements with dates) showed that I progress much faster than then, and I felt that I could definitely improve on my 888150 high score. At the time I felt more than 900k was possible and I wanted to get 1M+, but it was frustrating when the speed of a lander is so high that they take the last man up a very long way in short time and if you get killed often a lander still got to the top resulting in a mutant fest if it was the last man. Also, other things took my time from mid 1996 on. Well, I will try it this year... Shoot speed should, at a bit more than 1M, reach the maximum again so it will be difficult.

I made some videos, first with S5, then with S2 which is a bit blurry for some reason, whereas in short tests of recording Planetoid the video of the S2 was better than of the video made with my S5 (with S5 recording in low resolution).


In a bit of night play on 6-7 June 2017 I got 2 improvements for 2017: 812450 and 857300 (end of wave 50, the maximum tab bombs/lives I got to was 39/28). The large number of tab bombs meant a good buffer for situations such as not keeping the last man alive, as happened twice in the 857k game, in wave 47 most notably so a bit more than 2 waves in a mutant fest. I also wasted a few smart bombs accidentally pressing TAB twice (first time that ever happened to me during playing Planetoid, curiously). The score is very close to my 1996 high score, so my skills are definitely not worse than in 1996. I know for sure now that I can improve on my 1996 high score by a large margin because in both 800k+ games I was testing tactics and not playing optimally at all.

A while ago for a high score competition I also briefly tried Zalaga for several games and within a short time I got to just under 150k, whereas in 1995/1996 my high score was 154k. So, very close but I didn't try to improve on it as it is such a boring repetitive game, and I know I felt the same in 1996, which means that I didn't do much effort for a high score then, just as I didn't do much effort this year, and thus any comparison would likely not tell anything about the ability to play computer games now vs. then... (that fact was a big part of the reason why I didn't continue to play this game further to get a higher score in that competition)

2017-7-24: I think I can score 1M+ with the current strategy, but I have been analysing what I need to do to score much higher which would likely be needed if those scores of 2.8M and 3.1M are real. I've tested a new strategy with short play-testing (up to say waves 10-15), so far not succesful. If I get no result soon then I will go for 1M+ with the old strategy. Or devise a new strategy... [ Addition Nov. 2017: From testing with high wave numbers, the 2.8 M and 3.1 M scores are not real, or at least not made on a BBC micro with the BBC micro version of Planetoid ]

2017-10-21: Some practicing with different tactics, and no highscore from that but see my tactics page for more on that. I did improve my 2017 high score to 873,600 on 21 Oct. I would have improved my all time score if it was not for killing the last man at wave 50! (and before that at wave 30...) Aargh!

2017-11-12: I played a game, almost wanted to quit as after losing the first life at an OK score, the next 2 were too soon, but I continued. I got into a rhythm, experimented as I did a while ago with letting landers at higher waves pick up men too. I got to the highest number of lives smart bombs ever, by a large margin: 36l / 44b or even 37/44. It went extremely easy, it all was flowing, and I knew at ca. 700k already that I would improve my highscore as I had so many lives and smart bombs that nothing, including multiple mutant fests could spoil it. And I got to wave 53 with a score of 941,950, so, a higher average score per wave than in 1996. So my old score is history, cool. From how this game went I can definitely do 1.1-1.2 million (so, close to my initial rough estimate of the maximum achievable score). I got the hang of dealing with baiters at almost all levels. That's why I had so many smart bombs. The swarmers are still a problem.
Knowing that I would improve my high score made me play too relaxed, instead of what more often happens, which is adrenaline overflow. I read someone else mention the effect of shaking hands after about 30 minutes, well, yes, I've experienced that while playing 800k games when I was at the point of scores of ca. 600k-700k. That happens if play is 'hard work' instead of in my 941k game where it was going so easily. You need to relax and not try to do everything at the same time, i.e. at the start of a wave: 1) look after the last man, 2) kill all the bombers as I fly into them or their bombs too often, at the start 3) kill the landers, which are so fast that this needs near constant shooting. 4) evade the pods. This gives an overflow in the brain, just too much going on at the same time and at high speed! So you need to relax by just letting go and don't caring about e.g. the bombers and just see what happens, or use a few smart bombs to clear most of the aliens away.
In the 941k game I wasted a lot of the lives and smart bombs by using too many bombs and I was again too long in a mutant fest a wave 45-49 and 50-53 by again shooting the last man...

A few weeks later, I just played 2 games in that time, the 1st game 835k, the 2nd game 911k with a sub par number of lives/bombs (22/41 instead of a normal 30/35). I wasted a lot of lives/bombs in that last game again, from being for many waves in a mutant fest, so it confirms that 1M+ is possible even without the very high number of lives/bombs that I got in my 941k game.

2017-11-27: I was not playing as well as in my 941k game, but I was more concentrated and so used my smart bombs/lives better at 700k+ and scored 979,450 (I got to wave 56). This means I went past the highest score on Cool :) I got to 'only' 28 lives/38 smart bombs but I knew long ago that that would be good enough for a 1M+ score and if not for wave 47-49 and IIRC 53-54 and also 56 in a mutant fest (I still shoot my last man too often!), I would have done that. Planetoid rocks. It's the best adrenalin rush!

Comparison with Alligata's Guardian, the original Williams Defender arcade game and a few more BBC micro versions

Planetoid: Practicing and alternative play

Planetoid disassembly and patch

I found my disassembly from 1996 with complete list of all variables used, workspace, list of routines etc. Also included is a patch with fixes for a few issues that I describe further on. Using the disassembly I made a new patch that changes the score to 4 bytes for in case I go beyond 1M, at the moment the score is only shown with up to 8 digits in the high score screen. It could be useful for videos if the score is displayed as 8 digits in-game but I would want to check first what would happen time wise. All changes I made below have negligible effect on speed of the game, just a small number of cycles per game loop.

The current patch is v04 which fixes and upgrades the following:

Code to come (t.whsp03 / b.whsp03):
(1) Rename the file PLANET2 from Planetoid as O.PLANET2.
(2) Use the Basic file or *EXEC the text file, press Escape. You can select what you want to use or don't want to use by letting the PROCs execute, or by commenting them out. So modify the code if needed. SAVE the file as "B.whsp03" or do the modification when the file is loaded at &4000 as then the file won't reload itself.
(3) RUN. This saves the modified PLANET2 file. Now CHAIN "PLANET" will run the modified Planetoid. The patch version is shown at the bottom of the MODE 7 score screen.

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