Codetapper's C64 Site

Diary of a Game

Let's Make a Monster Part 8

Let's make a monsterAnd lo in the eighth month did the Apex Boyz say, "Let Monsterland teem with monsters." And thus did the genesis of a classic game continue...

It's time for a population explosion in Monsterland. We've already started designing the monsters, so now we've got to stick 'em in the levels. But we have to take the technical capabilities of the 64 into account. It's one thing to fantasise about 20 squillion monsters per level but there's no way the trusty 64 has the memory or the horsepower to achieve this.

So we've got to limit the number of baddies we use — but not by too much. If we only include a sprinkle of enemies in the game, it'll become too background-orientated. That's to say that the obstructions come mainly from the background and not the monsters, giving an empty feel. We have to tread a fine line between a possible level and a playable level.

Mega March 1993

Week 1

JOHN: Unbelievable as it may seem, I spent a few days this week tweaking Mayhem's control system (...again). You're probably wondering how Mayhem's control can possibly be improved anymore — it seems that every month I say that there's no way it can be enhanced any further. Basically that's why original games differ from conversions; the game structure is constantly evolving and changing. I find that if I sit and play with it for half an hour or so I always notice something that could do with improving. So now if Mayhem charges into a wall at full speed (which is pretty darned fast) he gets a puff of smoke in his face (well it was either that or a nosebleed). If he falls from a hefty distance he gets another puff of smoke under his feet (look I like smoke, okay?). I've also given him the ability to charge through invincible monsters if he's got a shield bonus. All these features give MIM an even greater sense of chaotic frenzy.

STEVE: At the end of last month I came up with an idea for a brand new level, which has big mountains (as tall as the screen) in the background. This is the level I'm working on now using some other discarded ideas I had a few months ago (when I was designing other levels). In particular I had another sketch of a tree with a big smiley face and arm-like branches resting on his trunk. This adds loads of character and makes it look like a 'tree with an attitude' (like that famous rapper Ice-Tree, then — Dave).

At the moment the tree is the only piece of vegetation on the level, so I need to be careful now — the rest of the level has to be in a style that fits in with this tree. I can't add lots of shiny platforms and background graphics because they'll look just a bit too, well, nice. So what I'll do is add some platforms with vegetation, and maybe some more natural background graphics until the level is populated enough with 'green stuff' (to use the technical term). This level has been christened Rockland — until I can think of something more suitable (er, like Treeland perhaps? — Ed).

Week 2

JOHN: Yo! I'm working on the monsters again (the little darlings have missed me). Instead of having to kill a monster to reveal a bonus, I've made it possible for bonuses to be placed on platforms, ready to be collected. I've also added some bonus modification routines, which physically alter the game according to the bonus Mayhem has picked up. These include the 'change set' and 'score multiplier' routines.

Once Mayhem has picked up the charge bonus he can charge at full speed around Monsterland. As he never loses this ability, the bonus will never reappear. But shields and score-multipliers can be picked up over and over again. If Mayhem has a shield and picks up another, his shield will restart. Score multipliers can be upgraded, increasing in value every time one is picked up. The first multiplies your score by two, the next by three, up to five. Unlike Creatures 1 and 2, MIM will feature MASSIVE scores!

STEVE: I'm still working on Rockland at the moment, adding some chequered backgrounds. I've put some green and yellow background panels into the level, with some clear water halfway down them. This effect is achieved by making the green and yellow chequers above the water blurred and out of focus and from the waterline down I gave the chequers a clear, crisp definition. To add that extra spark of realism I put some shine across the water surface.

I'm also starting to add some platforms which include slopes. I can use any characters from the character set to make the slopes, but there are strict parameters within which I have to work. I'm building up the slopes by placing three characters next to each other, then placing the same three characters on the screen again but up one and across two characters from the original position. This is repeated all the way up the slope. These characters are checked by John's code and Mayhem moves upwards when they're detected so it looks like he's walking up the slopes. (Check out the accompanying box.)

Week 3

JOHN: With the screen full of coloured, moving animated monsters, Monsterland is looking great! As Mayhem runs about, the monsters wrap around the screen - going off one side and appearing on the other. So the next routine I must write is my ALIOFF routine. This checks each monster's X position to see if it has scrolled off the screen, turning it off if it has. I've allowed a buffer either side of the screen before the monsters switch off (which is about two thirds of the screen in size). This allows my monsters to walk or fly around 'off-screen' so that Mayhem runs back towards them they will still be there!

STEVE: John's been compiling a list of extra sound effects we need to put in the game, and now it's up to me to create them.

First, I'm tackling the 'big jump' effect, which you get from the springboard aliens when you jump on them. This sounds similar to the jump effect, but is louder and slides to a much higher pitch, because you jump much higher.

Next on the list is the hit-count effect, which is a short high-pitched sound that mixes noise and triangle waveforms by 'wave flopping' (if you know what I mean, missus). Then there is the landing effect, which is a thud sound, which uses the pulse waveform mixed with a little noise for that bit of crispness. So now I'll give that little lot to John and see how they sound in the game, playing in all the right places over the level music.

These effects have to be tested like this for one reason; a sound effect might sound brilliant in the SFX editor, but it may be too quiet over the music (or may even clash with some of the notes). I will probably have to go and change any incorrect effects after we've heard them in the game.

Week 4

JOHN: We saw a demo version of Trolls this week having heard claims that it was the greatest C64 platform game ever (er, we never said that - Ed). So, with some trepidation we booted it up. Our verdict? Well it isn't bad, but it certainly isn't the best platformer ever. Mayhem in Monsterland has a larger playing area (the entire screen) with more colours (including some non-standard C64 colours) and runs twice as fast!

Anyway, back to what will be the greatest C64 platform game ever (biased? Never!). ALIOFF has been coded, so now I've got to map the monsters on to the background maps. This adds another type of map - monster maps - that have to be contained in each level, effectively being overlaid over the background. This routine, known as a sequencer, needs to handle both left and right directions with eight different speeds and still position each monster at the precise co-ordinates we want them. I've decided to get it working in one direction, then duplicate and modify the code for the other direction. This simplifies the initial design and is therefore easier to debug (I hope/wish/pray).

STEVE: You may remember a screenshot a few months back of Spottyland. This was a mock-up screen created using our graphic editor which means that we can't incorporate it into the game until I've converted all the graphics into blocks (explained in CF31). Once these blocks have been created I still need to create a basic level map to see a rough scrolling version.

Every block I define needs to be documented on paper with a number, a short description, a sketch and in some cases a table of how to join it to other blocks. This could take up to a week to complete, then an extra couple of days just to make a temporary map to see if all the blocks join together. To coin a phrase - ho hum.

Next Munf

The next instalment sees the continuation of the monster installation (hey that rhymes). We've also decided to put in a feature which enables us to produce levels of unlimited length (wow!).


PIC: A self-portrait by John (who forgot to use a tripod)

PIC: Monsterland is finally living up to its name. No wonder things are looking so grim.

PIC: Mayhem's brought happiness to the land, but there are still some monsters to avoid.



John and Steve Rowlands, aka Apex, aka those too clever by half coders who bought you Creatures 1 and 2, are in the process of writing their next blockbuster Mayhem in Monsterland. It's going to be a platform romp that'll put the Marios and Sonics of this world to shame. Don't believe us? Then we'll let the Boyz (ah, that's another one of their aka's by the way) tell you all about it themselves...



As Steve mentioned this month, creating slopes is not as simple as it may at first seem. There is a restriction placed on what characters can be used where. Mayhem looks for these special characters and, if found, the slope routine is kicked in. Mayhem will then continuously check which characters are around him and adjust his Y (up and down) position on-screen according to his speed. If 'off' characters are found, then he reverts back to his normal movement (where his Y position is modified if he jumps or falls only). These special characters need to be checked for constantly, allowing Mayhem to, for instance, land on a slope and then walk up or down it.

Steve's responsible for the visual style of the game. But he can't let his imagination run free; there are rules he has to follow, like placing control characters in the slopes so that Mayhem knows when to start walking up or down them.

PIC: This might look like any old slope to you, but...
... hidden inside are some very cunningly hidden control characters.

Series Links

Part 1 / Part 2 / Part 3 / Part 4 / Part 5 / Part 6 / Part 7 / Part 8 / Part 9

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