Operation Wolf: Dissecting a classic

(deep breath) OK, one day down, 4 to go.

If I’m going to do a Lego-style remake of Operation Wolf, then I need to do my homework.

One of my pet hates with game remakes, is when the “new” game doesn’t play like the old game. Sometimes it’s hard to work out exactly what’s wrong. So you try the original title again, and you notice the differences.

Perhaps the baddies move too fast.. or the bullets go too slow. Maybe the scenery is larger, or weapon X is weaker than it should be. I’m not insisting on 1:1 pixel perfect remakes – otherwise you might as well emulate the original. But if XYZ-The Remake ignores all the little things that made XYZ great, then I’m not a happy camper.

Anyway, enough game remake philosphy. Lets see what I actually did when I started the Operation Block project.

First of all, I googled the original arcade manual. This gives me the ruleset, the scoring system.. and reminds me of small details that I might have overlooked. The game manual is like a listing of chapters in a book; each one contains many small parts that make up the overall experience.

The original arcade games manual is a good place to start.

The original arcade game's manual is a good place to start.

Next, I loaded up Operation Wolf on MAME. (And I thank Nicola Salmoria every day for his wondrous gift to retro gaming.) I can only marvel at the people who did “ports” of arcade games in the 80’s and early 90’s without it. They very rarely had the original machine available to play in their office. Instead, they’d often rely on documentation and videotapes(!) of the game being played.

As I played through Operation Wolf, I took many screenshots and short videoclips. The screenshots were pulled apart for a few reasons. Firstly, I cut out the sprites, in order to print them out for reference later. Things like buildings, vehicles, enemies and powerups. You can see my “high-tech” referenceboard on the left – in the photo below.

Designing characters in MLCad, using original Op Wolf backgrounds & characters for reference

Designing characters in MLCad, using original Op Wolf backgrounds & characters for reference

Hmm, I actually blew my $0 budget when I printed those photos… I think it was AU$6.50. Wait till my investors hear about it!

*Moving on…

Besides getting the sprites for referencing later, I also needed them for measuring. Part of my “recipe” for a classic game is the ratio of the sizes of various sprites to each other. If I made a Donkey Kong remake with a Jumpman (Mario) character half the size of Kong, then you wouldn’t be as intimidated as you should. So – I measured each of the original sprites in pixels, in order to make sure the replacement graphics seem “right” in the Op Block world.

Measuring level 1s large grey building

Measuring level 1's large grey building

Despite my simple diagram above, you can probably identify that building, if you’ve played the first level of Operation Wolf a few times. I’ve worked out how many pixels each component takes up.. ie windows, doors, walls, the staircase on the right, etc. This is pretty much the technique I used for all the items in the game. Later on, when we’re up to the “block building” phase, we’ll need those measurements again.

Enemy quotas for each level need to be broken down into enemy types.

Enemy quotas for each level need to be broken down into enemy types.

Anyone who’s played Op Wolf a few times would be familiar with the “quota” system for each level. ie Level 1 = X men, Y tanks, Z helis. But of course, it’s not that simple. There are tanks from the left & right of the screen. Four different helicopter patterns. And – many, many different types of human baddies.

Operation Wolf seems to vary which baddies it sends (& in what order) each game. Unfortunately I don’t have access to any high-level documentation to explain how that works. So – I’ve recorded (video) one full game at this stage, and my level 1 prototype mimics all the baddies and patterns for that particular session. Later on in development, I’ll make sure there’s enough variation to take players by surprise.

Early notes on one of the four patterns used by Op Wolfs helicopters

Early notes on one of the four patterns used by Op Wolf's helicopters

I mentioned before counting the number of each type of enemy. I also had to track the movement of each vehicle. eg Tank type 1 starts on the left, moves right X pixels, starts rotating turret, aims at player and fires, rotates turret back, and exits screen right. The pic above shows some of my very rough notes on one of the helicopter movement patterns. They’re amongst the most fiddly things to get right in the game.. but of course, that’s talking programming.. which is a later topic.

Early notes on the spread and damage pattern, for the rocket weapon.

Early notes on the spread and damage pattern, for the rocket weapon.

Your weapons are also part of the game’s “feel” and above you can see my rough diagrams of how the damage model for the rockets works in three stages. How did I test this? By trying multiple games in which I would fire the rocket at a group of 4 windows. The panes of glass would (or would not) “smash” depending on how far they were from the 3 damage patterns, and how far the rocket’s explosion animation had progressed.

So, I’ve measured the size of the various game elements, their movements and their ability to damage each other. Now, it’s time to measure.. time! Here’s an example. If you press the machinegun in Op Wolf, how fast do the bullets fire? What about if you pick up the “FREE” speedup bullets? To test this, I timed how long it took me to “waste” a full magazine of 30 bullets. I then calculated how long the delay was between each bullet, and put that into the game. BINGO. The Op Block machinegun fired at the same speed as the original.

Seriously! Theyre really useful for speed matching.

Seriously! They're really useful for "speed matching".

Ok, so that was a bit of a “dry” post today. Don’t worry, as we progress in this project, there’ll be plenty of fun posts, and maybe a chance for YOU to get involved in Op Block.

More on THAT much, much later.

Disclaimer: Operation Block is a freeware, fan tribute game being developed for Windows PCs. There’s no connection whatsoever to Taito, Lego or Traveller’s Tales. And it won’t be ready till Christmas 2010. At the earliest.

Hope you enjoyed Day 2 of “International Operation Block Week”.

…well, I can’t give away everything at once. 😉

PS: If you’re excited by Operation Block, please consider giving it a “digg” or a “reddit“. Thanks!

*CC Stopwatch image by Flikr user nDevilTV.

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