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PAL-NTSC Conversions


Lucky Man

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  • 7 months later...

Today I did a much better conversion of X'Mission. This one runs at 262 lines making it compatible with everyone's TV's. I also fixed some playfield graphical glitches from the original. :)

 

 

I.e. some glitches circled in red:

 

post-7074-0-11098900-1352674633_thumb.png

 

 

 

Xmission (NTSC) rev3.bin

 

 

X'Mission can be challenging until you figure out a few strategies. What I usually do is:

 

Starting level:

- Kill the aliens quickly before they fill out the wall.

- As you will soon learn, your bullet bounces back in X'mission. Watch out!

Hidden Wall level:

- Stay to the far right and blast away until the aliens are dead. Try to get out of the way when you seem the aliens coming, and if possible stay above them to avoid their laser beams.

- After the aliens are dead if the dock is in the upper portion of the screen, enter the bottom portion of the hidden wall (and vice-versa). Move your ship so that it is partially covered by the black wall, but not so far out that the dock can collide with it. Now you just need to move up\down into position, and then quickly dock.

Level 3:

- Lightly touch the firebutton so that the level starts. Holding the firebutton sends a shot off (which rebounds and kills you).

- Dodge the aliens and dock immediately. It is too tight in this level to try and blast the aliens.

- Watch out for the wall fast approaching from behind. This level can be tough!

Solid Wall levels:

- Kill the aliens immediately, so you can focus on carving out the wall.

- After the aliens are dead move close to the wall, but not so close you can't get out of the way of your bouncing bullet. The closer you are the less time it takes to punch a hole through. Use the surrounding objects to stop your ship moving up/down. The idea here is to use the them as a guide for your ship to blast a straight line in the wall. So move down until you stop on a piece, fire, immediately move up and let the bouncing bullet pass by you, move down again, repeat.

- The hardest level is when the wall is completely solid, as it is easy to run out of time.

 

 

 

 

The other levels are variants, but only level 3 and the full solid wall are particularly tough.

 

 

 

Enjoy!

Omega

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Thanks a lot for this! I just played this for the first time last week.

One of the strangest playfields / game concepts I've seen.

 

X'Mission is a strange beast. At first it is easy to write off as it looks childish, but the game can be a lot of fun (especially the solid wall levels).

 

 

I just noticed that in demo mode on level 3 the wall pattern starts to differ from the original after a while. I'll have to address that at some point. The original game uses code as data to move the wall around. I took the game, expanded it into 8k, and then placed all of that data as HMOVE values in the second bank (along with the kernel). This allowed me to modify the code while still retaining the original look of the game. 8k also gave me a huge amount of room, so I took alot of subroutines and placed them as copies inline to speed things up a bit, and to get the code to run at 262 lines.

 

 

I also moved some code from Overscan into VBLANK since the amount of time got quite short in Overscan. The screen is very tall in this game. One of the modifications I did was to make the top and bottom borders thinner. This seemed like a good solution to try and get as much game area on screen as possible.

 

 

Other mods I did were to slow the vertical movement of the aliens. This made the game more playable IMHO. Also when you first start level 3 if you let go of the firebutton quick you won't let a shot off. The original always fires a shot here and you often die. I'm not sure how this change occured in the code, so right now it is a "happy accident" ;)

 

 

There are still some todo items left. The original game kept the score stored in 2 registers $EF, and $F0 as straight up hex values. I did some quick look up tables to convert these in Overscan as I really needed the cycles, but it was a super expensive 5 pages of data. :-o Given the time I have these days it was a viable solution. :P One day I will convert the game to just store the score in BCD (three registers) and free the rom space back. To the user this makes no visible difference in how the game plays. However, one change that would be visible to the user is improving the collision detection. I would like to implement some nice software collision at one point. Then I would move on to converting the sound better. Finally I would probably put some of those subroutines I placed inline and make them subroutines again, if the cycles were still good. Right now I wanted to really ensure I had ample cycles.

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  • 3 years later...

*Bumpity!*

 

Thomas has fixed the rolling problem in Col'N (Alien's Return). This isn't based on the original PAL ITT Home Vision version, but the supposedly NTSC pirate version. It no longer rolls when all 4 aliens are on the screen.

 

BTW, in case you don't know how to play it, here are some instructions in another thread:

 

http://atariage.com/forums/topic/59639-what-the-deuce-is-going-on-in-aliens-revenge/?p=729301

 

And in addition to that, the large block that appears in the middle replenishes the blocks you can drop to slow down the aliens.

 

Enjoy!

 

 

Col'N (NTSC fix by Thomas Jentzsch).bin

Edited by Lucky Man
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  • 1 year later...
  • 5 months later...

Okay, we've finally done it! Here's the last game, Words-Attack! Brought to you by Omegamatrix. Thank you, sir! (Note: To reduce the scanline count it was necessary to eliminate the boxes at the top of the screen which are used for the letters, lives and score of the 2nd player that you can choose by moving the right difficulty switch to A. So this conversion is just for 1 player.)

 

So unless someone finds another obsure PAL game we've never heard of, we're done! Thanks for all of your help with these everyone!

 

WordsAttack(2018_05_27).zip

 

EDIT: Attached updated rom that fixes 2nd player boxes. Yay!

Edited by Lucky Man
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  • 2 months later...
  • 1 year later...
8 hours ago, kevates said:

I downloaded this NTSC conversion of Walker - and tried to play it on my harmony cart - it seems to be PAL and not NTSC - does a better NTSC conversion of Walker exist?  - Kevin

 

 

At 285 scanlines it's neither PAL (312) nor NTSC (260), but somewhere in between.

 

1086407638_ScreenShot2020-07-30at10_02_42AM.thumb.png.18bb34a1b039af5932be309ecb883297.png

 

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