Sokoban (NEC PC-8801 & Fujitsu FM-7)

Penetrator (ZX Spectrum) - Z80 Block Copy is slow

https://www.youtube.com/watch?v=-AvJFKq3gC4&t=461s

@john2001plus
3 days ago (edited)
7:41  I played this game on the Timex-Sinclair 2068, which I purchased around the beginning of 1984 or the end of 1983.   The TS2068 isn't necessarily compatible with Spectrum games, but it could have been a port.  Maybe the sound was better because the 2068 has a sound chip.

If you did well, you got a fireworks show at the end.  We see this in the video, but I thought it was better with sound.

I may have played with the keyboard, which is how I usually played games.

The barrier on level 5 appears to be the end of the game.  I remember this now.

Given the hardware, I'm impressed with the scrolling.  I was impressed in 1984 because the block memory copy on the Z80 processor is super slow, which is how you would scroll the entire screen, although I can think of some coding tricks to do a slightly faster memory move.


@chronologicallygaming
14 hours ago
Great memories—and you're spot on. The TS2068's AY sound chip really does give it an edge over the standard Spectrum beeper, so that fireworks ending absolutely would've hit harder with proper sound.

And yeah, Spectrum compatibility was always a bit of a gray area on the 2068—very possible this was a port or at least heavily adapted. Keyboard play makes total sense too; that's how a lot of us tackled these back then.

That level 5 barrier lining up with the end of the game matches what we're seeing, so your memory's right on target. And agreed on the scrolling: for Z80-era hardware, especially with block memory moves being so slow, it's genuinely impressive. You can tell the programmer knew a few clever tricks to squeeze out performance.

Thanks for sharing, John. This is exactly the kind of firsthand detail that brings these games to life.


@john2001plus
14 hours ago (edited)
@chr@c @chronologicallygaming  I had a lot of Z80 programming experience.  I got to do it again on the Gameboy Color. It is a little easier to program than the 6502, because it has more registers and instructions. However, the 6502 is about twice as fast per clock cycle.  It was designed to be cheap and fast.



@john2001plus
3 hours ago (edited)
 @chronologicallygaming  The 16K video memory on the 2068 and Spectrum is contested memory, which means that the display chip has priority.  If you try to access the video memory while the display is being generated, then the processor will freeze until the horizontal or vertical blanking period.  

It is possible to swap memory banks in such a way that the vertical blank interrupt runs your code instead of ROM code.  This is a trick I didn't know back in the 1980s, but it would be useful for running all the video memory writes in the vertical blanking period, avoiding any processor halt.  (If most of the processor time is spent drawing to the screen anyway, such as my Diamond Mike game, then this trick might not help much.)

Unfortunately, BASIC code starts in the contested memory, which will affect the speed of BASIC programs.  I have read that there is a piece of ROM code that you can call which will relocate BASIC to the top 32K memory, which is uncontested memory.  This would make BASIC a little faster, but with less free space.  I wish that this had been the default, but that code in the ROM exists for a reason, so maybe they expected some people to use it.

The problem with the Block Memory Copy is that it does too many steps for every byte moved.  It moves a byte, increments two pointers, decrements a counter, and loops. This takes 21 clock cycles per byte.  However, if you knew that you were going to move a fixed number of bytes, such as 32 bytes on a line, you could write code that would move 32 bytes without looping.  Then you loop for each line you need to move.  

You could take this idea to a more extreme level, where you move 256 bytes without looping, but it would take 1K of code.  However, the computer has kilobytes to spare.

If you need to write the same bytes to a block of  a memory, such as the clear screen command, you can temporarily hijack the Stack Pointer to do it faster.  This only takes 5.5 clock cycles per byte.  (I suspect that the BASIC clear screen command uses the slow block copy instruction, because it is not instantaneous.)

Mouse Trap (Intellivision)

Why Do We Say "Sprites"?

https://www.youtube.com/watch?v=tTqfeJ2yJwE&t=100s

The word "Sprite" originally referred to fairies or spirits.  Within games, a sprite is a 2D object that can move independently from the background.   Your mouse cursor is a sprite.

It was obvious to me that "Space Invaders" did not have hardware sprites, because it moved the invaders one at a time instead of moving them all at once.  This led to a reportedly unintentional bug that became a feature;  as invaders were eliminated, the remaining invaders moved faster because there were fewer objects to move.

Two computers that I wrote games for in the 1980s did not have hardware sprites.  This puts the game at a disadvantage because the code has to draw objects to the screen, which is technically difficult and burdens the CPU.  This limits what an 8-bit computer without hardware sprites can do.  

I wrote software to emulate hardware sprites on the Atari ST.  Since it was a 16-bit computer, the extra computer power made this task easier.  Once computers and game systems reached 32-bit, they usually didn't bother to include hardware sprites because the processors were powerful enough to draw anything they wanted to the screen.

Deep Sea Adventure (CreatiVision)

E4M5: They Will Repent

@john2001plus
0 seconds ago
I was not liking this E4M5 map because of the apparent complexity.  There are areas that have layered mazes, where you have to drop down to explore lower paths.  This map seemed like a very confusing maze.

Part of the problem was with me; I tend to not study the map and just explore.  However, after I finally carefully studied the map, I understood the different rooms much better. The big room on the left was what confused me the most.  It has 5 entrances and 1 or 2 windows, making it look like a somewhat different room from each entrance.

There are only 2 secrets, which at first are hard to find, but once you learn where they are then the map is easy.  The keys are also easy to get, and you don't even need the yellow key to finish if you jump through a window to the exit.

I've changed my mind.  This is a brilliant map.  The complexity might put people off at first, but it is not near as hard as it looks.

Penetrator (ZX Spectrum)

@john2001plus7 minutes ago
7:41 I played a game that looked similar to this on the Timex-Sinclair 2068. The TS2068 isn't necessarily compatible with Spectrum games, but it could have been a port. I think the sound was better. If you did well, it gave you a fireworks show at the end.

Qix: Secret Strategy

https://www.youtube.com/watch?v=GUHoYanzPgg

Shark! Shark! (Intellivision)

The Complete Vector Arcade Journey

https://www.youtube.com/watch?v=swryO4xWOTk

E1M7: Computer Station

@john2001plus
After not playing Doom for at least a couple of decades, I have been alternating all the Doom and Doom II maps.  I am averaging about two maps per day.

Doom II is about twice as complicated and twice as hard as Doom.  Some maps take 45 minutes to get through.   By comparison, "Knee Deep in the Dead" seems pretty trivial to finish.  E1M7 might be the most complex map in the first episode, which makes it fun.

Because of the complexity and difficulty of Doom II, Doom feels like the better game, but Doom II has more replay value.  It takes longer to master.

The 4th episode of Doom, Thy Flesh Consumed, which was released as part of "Ultimate Doom" in 1995, is more complex and more difficult than the original Doom episodes.    The first three maps are very hard.  It has Doom II difficulty without being too complicated, so it is my favorite.

The Doom Clone Which Came FREE In Cereal Boxes (Chex Quest)

Doom II Map26: The Abandoned Mines

@john2001plus
8 minutes ago

Since half of the map consists of metallic cages with monsters behind them, along with some secret passageways, it felt like a confusing maze that I didn't like very much.  I thought that the map was annoying.

However, on my 5th or 6th attempt, I understand the map better and it is not nearly as difficult as I thought it was.

The key is that near the middle of the map there is a crossroad that connects four distinct areas.  Once I understood this, it became easier.  One of these areas just contains the exit and another is the starting area.

In terms of trickiness, the starting area has a couple of secret passageways behind walls, which lead to some monsters to fight.  In these areas there are three teleporters that you might want to take.  One leads to weapons on high pillars, and another takes you to the only outside area.

Now that I understand the map better, I like it.  However, there are so many ambushes with chain gunners and cacodemons, you have to tread carefully.  It is definitely a challenge, but a welcome one.

The map that follows, "Monster Condo", might be the most difficult of the whole game, not counting "Icon of Sin."  There are too many monsters to fight, and a couple of areas feel like deathtraps.  I kind of dread playing this map.  On my previous attempts I would be low on ammo forcing me to get very creative in my combat, but it is not as much of a problem this time around.

Deck The Underhalls | Christmas Slaughter Maps??? | Doommas Season

Doom II Map13: Downtown

@john2001plus
12 minutes ago 
7:11  There is an easter egg of sorts.  If  I get a full running start, I can jump to the right cage.  It doesn't accomplish anything, but it would be nice if it did.

For newcomers this map is frustratingly complicated.  Some YouTubers hate it.  However, I've had enough repetition to understand what I need to do.  Or roughly my 6th attempt, I was able to complete the map without any guidance.  

I usually have less ammo at the start, so I go around picking up ammo while killing as many enemies as possible.

10:17  However, this is the one secret I frustratingly could not find.

Playing this game again makes me happy.

Wizard of Wor (Atari 2600)

Happy 32 YEARS To DooM!

Walkthrough (E3M7: Gate to Limbo)

@john2001plus
1 minute ago (edited)
Many YouTubers hate this map, with some describing it as one of the worst maps in Doom 1.  I was also initially frustrated with the map, because just like Unholy Cathedral which some YouTubers describe as the worst map in Doom, figuring out the multiple transporters is more frustrating than fun.  People also hate the Pain Lava on this map.

However, now that I know what to expect, I have come to really like both maps.  If you can remember where the transporters take you, the maps aren't that hard.  Both maps are unique enough to make them interesting and fun to explore.

With enough repetition, what seemed frustrating becomes easier.

Ultimate Doom (100%) Walkthrough (E4M1: Hell Beneath)

@john2001plus
30 seconds ago
I have been alternating all the Doom and Doom II maps, starting on the easy difficulty and advancing to the next difficulty on the next pass.  I am going to continue until I either master all the maps or get tired of the game.

This is the third time I played this map on Ultraviolent, but it is the first time I got 100% without losing almost all my health and ammo.  This makes a big difference on the next map which is a tough one.

Xevious (Arcade)

How Did StarFox Have 3D Graphics?

https://www.youtube.com/watch?v=0GmSdB6zzrs

History of CreatiVision

https://www.youtube.com/watch?v=8DjEyIs23po

MSX

Nishi's standard was built around the Spectravideo SV-328 computer.[16] The standard consisted primarily of several off-the-shelf parts; the main CPU was a 3.58 MHz Zilog Z80,[17] the Texas Instruments TMS9918 graphics chip with 16 KB of dedicated VRAM, sound and partial I/O support was provided by the AY-3-8910 chip manufactured by General Instrument (GI), and an Intel 8255 Programmable Peripheral Interface (PPI) chip was used for parallel I/O such as the keyboard. The choice of these components was shared by many other home computers and games consoles of the period, such as the ColecoVision and Sega SG-1000 video game systems. To reduce overall system cost, many MSX models used a custom IC known as "MSX-Engine", which integrated glue logic, 8255 PPI, YM2149 compatible sound chip and more, sometimes even the Z80 CPU. However, almost all MSX systems used a professional keyboard instead of a chiclet keyboard, driving up the price compared to the original SV-328. Consequently, these components alongside Microsoft's MSX BASIC made the MSX a competitive, though somewhat expensive, home computer package.

https://en.wikipedia.org/wiki/MSX

Is the NES Mario Trilogy Bad?

Ranking the DOOM (1993) Levels (and Bosses!) from Worst to Best

@john2001plus
42 minutes ago (edited)
1:37  Thy Flesh Consumed is my favorite Doom Episode.  It has some of the best maps, although the difficulty is higher.  It is sort of a middle ground between Doom and Doom II.  I love it.

I am able to play the original three episodes on Ultraviolent with no problems.  However, Thy Flesh Consumed is very difficult on Ultraviolent.  Nevertheless, I can get through it.

Against Thee Wickedly, E4M6 is my favorite map in Doom 1 and 2.  It is big and complicated, but follows a logical progression.

Halls of the Damned is maybe my least favorite map in Doom.  Maps with confusing mazes, especially dark confusing mazes, I find frustrating.  There are ambushes everywhere, and that seems to be the only point of the map, and you have to memorize all the ambushes to get through it.

It is possible to kill the Spider Mastermind with just a couple of BFG shots.  You can finish the map in seconds.

I discovered a way to beat the Cyberdemon with hardly any effort.  It involves shooting him with rockets from across the middle section. You stand just outside one room, fire through the doorway over the middle post, and hit the Cyberdemon in the opposite room.  Your shots pass through three doorways.  His rockets hit the metal post in the middle, so you are mostly safe.  You may have to kill a few Lost Souls at the beginning.

Map30: Icon of Sin

@john2001plus
14 minutes ago 
If I couldn't beat this map on the third level of difficulty, then technically I couldn't beat it on the 4th level of difficulty.  I got that last shot off as I died and the game was won.  However, that last shot and only the last shot was a bit of a cheat.  From the top of the platform, I used the look down feature on gzdoom which just happened to be at the right angle and I made the shot.

This map is sadistic.  I am getting absolutely shredded.  I can't fight the enemies and get on the platform and time the shot all at the same time.

There are too many enemies and too little health.  It is overwhelming.

I remember beating Doom II thirty years ago.  I suspect that it was the easiest difficulty.  Doom II was not interesting enough to me at the time to keep playing it.

Map29: The Living End

@john2001plus
1 second ago
11:18  I had no problem picking off the mancubus ahead of time.

I can see why this would be the favorite map.  Despite the very large size, it is an easy map to understand what you should do next.  There are no confusing mazes.  Instead you are exploring the map in a mostly linear fashion.

This was my first time on Ultraviolent, but the map doesn't seem difficult.  You just have to proceed slowly and be cautious.  

I'm not fighting the cyberdemon at the end because it is optional and I'm not suicidal.

9:30  I don't understand how you can so efficiently do a circle strafe.  That feature is not available with the keyboard, but maybe it could be done with a special controller?

Map28: The Spirit World

@john2001plus
0 seconds ago
Getting through this map on Ultra-Violence with limited ammo is quite a challenge. When I reached the area with the Spiderdemon, twenty Arachnotrons, and several other demons, I thought I had finally hit a wall and wouldn't be able to finish. But somehow, I pushed through. Once again, I had to get creative—lots of hit-and-run tactics—and the invulnerability spheres along with monster infighting helped tremendously.

The two rooms at the beginning seem designed specifically to shred you. Even with the BFG, I lost a significant amount of health.

There are probably optimal routes or strategies for these maps that I haven't taken the time to memorize. Next time, I may refer to your videos more closely.

I still prefer the first Doom, but these Doom II maps are definitely more intense.

The confusing layout of this map didn't appeal to me at first, but once you learn where everything is, it becomes much more manageable.

Map26: The Abandoned Mines

@john2001plus
2 minutes ago
Now that I have beaten it on Ultraviolent, I find the combat interesting, but the only real bright spot is the big pair of rooms with the winding walkway. 

I found the cage-and-poison areas to all look too similar, and combined with the many secret passageways and teleports, it is all a bit too confusing.

The chain gunners are not a welcome addition to the game. There are several ambushes and if you don't kill them immediately you are dead. 

If I had everything memorized, and I don't, the map would be easier. However, if I played the map that many times, it wouldn't have much appeal.

Doom II (100%) Walkthrough (Map24: The Chasm)

@john2001plus
51 seconds ago
This is not a difficult map to finish.  It is very large and is fun to explore, but also takes much effort to fight all the monsters.  The multiple ambushes are dangerous, but if you know what to expect then you can deal with them.  It is very straightforward and it is always clear where you need to go next.

It is ten times easier than the previous map, Barrels of Fun, and it is likely easier than the next map, Blood Falls.