Space Invaders / Connect-4

[Lechuck]

Much better - 3620 on my first go on the new one.

Still seems a little too easy but it is enjoyable - is the shooting / missile a little too fast with little delay between shots?

Thanks Ian,

yes, you are right. I hadn't realized that but, yes, in the original one, there is some delay between a shot is completed and the ship can fire again. I'll try to change that but I'll need to find a way to save some memory before (just one byte free right now )

Cheers

[Vic20-Ian]

You could switch to 8k expansion, more common than 3k.

[Lechuck]

I compared it against the 1978 Tatio Original in MAME and noticed a few of minor differences:

- On the original, the alien explosion effect lasts about 20 frames or 1/3 of a second during which time you can't fire again.

Yes, you are right. I haden't realized about this. As mentioned above, I'll try to do it if I'm able to save memory in other parts...

- The base ship can move slightly faster, covering the width of the screen in 5 seconds compared to 6 on the Vic.

Again true. I have increased ship's speed a bit. Uploaded a new version

- On the original there is a point where the first and last column of the Aliens cannot be shot as the range of the base is restricted.

Yes, that's true but, in this case, there is a good reason ...

I'm using 23 columns (2 for every alien + one free to the left of the first alien). That way aliens will be able to move 8 bits to the right and, then, 16 bits to the left (as they do in the original game).
Then, there are 4 buildings, 3 chars width each (I tried with two chars but they looked too small). That leaves 11 chars for the space between buildings + space to the right and to the left of the group of buildings. So, I might use 4 chars before and after the group of buildings and 1 char between buidings, but buildings would be too close to each other. The other option, was to use 1 char before and after the buildings and 3 chars between buildings (this looked better and it is what I used). But, since there is only one char from the start to the first building, if I avoid the ship moving to that first column, it wouldn't be able to fire to the left of the first building, which is different from the original game. Hence I decided to allow moving to the first/last columns (and yes, you are right, this makes the game easier...)

Thanks a lot for all your comments and analyis

Cheers

[Lechuck]

I am still blown away by how accurate this is though after playing Alien Blitz and Avenger for the last 35 years or so
This has to be the best home computer version I have played.

Thanks!. That's very kind of you!

[Lechuck]

You could switch to 8k expansion, more common than 3k.

Yes, sure!. But I thought it would be nice trying to do it with as little memory as possible (in fact I first tried it without memory expansion but soon realized I wouldn't be able to get it).

Cheers

[beamrider]

Yes, given what you have said, you would have to make substantial changes then having the bases lying across character boundaries, perhaps pushing the game up into the 8K requirement bracket.

No worries, it's a fantastic game as it stands and the fact that we are pointing out such very minor differences speaks to this.

[Lechuck]

Yes, given what you have said, you would have to make substantial changes then having the bases lying across character boundaries, perhaps pushing the game up into the 8K requirement bracket.

No worries, it's a fantastic game as it stands and the fact that we are pointing out such very minor differences speaks to this.

Thanks Beamrider,

I really appreciate all the comments. It is great to improve the game based on them.

Regarding the first/last column issue, I think easiest option will be to switch from 23 to 25 columns. That shouldn’t be complex, and would leave first/last columns available for aliens, while still allow the ship to fire left/rigth to the group of buildings without reaching both ends of the screen. Only problem is that I’m already using the unused screen memoy for some of the source code, so,I’ll need to find the way to save these additional 54 bytes (I’m currently using 27 rows). Hopefully, I will be able to find those extra bytes. Interesting to try, anyway, to keep having fun programming the VIC.

Cheers

[Lechuck]

Hi,

I've just uploaded a new version of the Invaders game. Same link as before.

Changes from the previous version are:
- A certain delay between base ship's shoots
- Base ship, now, cannot move to first/last column, so, there are certain positions where aliens cannot be destroyed
- Begining every screen, or when the base ship is destroyed, there is a certain delay, while Aliens are moving but the ship is not drawn yet.

Thanks for pointing out these differences between previous version and the original game.

Cheers

[beamrider]

Thanks for this. Looking good, although the invader explosion still seems not quite right?

The reload delay should constitute the alien exploding for ~1/3 a second with the explosion graphic shown, then it should disappear and you can fire again...

[Lechuck]

Thanks for this. Looking good, although the invader explosion still seems not quite right?

The reload delay should constitute the alien exploding for ~1/3 a second with the explosion graphic shown, then it should disappear and you can fire again...

Hi Beamrider,

Yes, that’s true. In the original version, when an alien is destroyed, explosion is kept for a while and, during that time, remaining aliens don’t move and we cannot shoot. In my version, I put the explosion and keep it for a fixed period of time OR until aliens have to move again (in that case, I hide the explosion before moving aliens). So, when aliens are moving faster, explosion is barely visible and shooting delay is less noticeable. Hopefully, it won’t be dificult to mimic that part too. Will have a look.

Thanks for the feedback!

Cheers

[beamrider]

Yes, just the Alien movement is suspended (ship, bullets and mothership still move).

I guess you just need to not call the "move aliens" routine for 1/3 second while the explosion is being displayed.

[huffelduff]

Just uploaded a couple of 'new' games:

Hi there Lechuck,

Awesome work on the game. As has been pointed out, this sets the bar for Space Invaders on the Vic.
So much so that my version that I'm working on I have paused to rethink it carefully.

Anyhow great work.

Greetings

[Lechuck]

Hi there Lechuck,

Awesome work on the game. As has been pointed out, this sets the bar for Space Invaders on the Vic.
So much so that my version that I'm working on I have paused to rethink it carefully.

Anyhow great work.

Greetings

Thanks for trying it, Huffelduff. And thanks a lot for the feedback. I’m glad you liked it.

Loooking forward to your version…

Cheers

[Lechuck]

Yes, just the Alien movement is suspended (ship, bullets and mothership still move).

I guess you just need to not call the "move aliens" routine for 1/3 second while the explosion is being displayed.

It is done now (hopefully )...

Uploaded a new version.

viewtopic.php?f=15&t=9974&start=15#p113397

Cheers

[beamrider]

Amazing!

Look and plays identical to the original to my eyes.