Hacking Activision's Tennis: some proposals

[+thegoldenband]

One of my pet projects is checking out various tennis games for older consoles. There have been some pretty miserable examples of the genre (SG-1000 and NES, I'm looking at you), but Activision's Tennis for the VCS is definitely one of the more enjoyable ones.

 

The game's been the subject of commercial and homegrown hacks in the past, most notably the Home Vision version (PAL), which expands the ROM from 2K to 4K, astonishingly adds an entirely new scoring screen (which is great!) plus a little tune (which...isn't). And plenty of people have done various graphics hacks.

 

But I think the game is a prime candidate for a gameplay hack to give it a little more depth. The mechanics of the game are great, but because there's really only one variable -- the angle at which you strike the ball -- you can end up with long rallies in which there's no long-term strategy. So here are some ideas that might deepen the gameplay somewhat:

 

• Adding a little bit of inertia when your player changes directions. This would need to be subject to playtesting, and might not pan out, but it could encourage people to go for bigger shots, since your opponent might not be able to catch up to a surprise angled shot as easily.
   
  
• Having your player get a bit slower as the rally progresses. Again, this may or may not be fun in practice, but it certainly mirrors the way real-life tennis works. If your style is endless retrieving and waiting for the other player to make a mistake, eventually you'll either have to go for a big shot or simply be outgunned. This could also be implemented via increasing inertia, as above.
   
  
• Introducing additional characters, differentiated by color, with strengths and weaknesses. It seems to me that this could be done via the Select switch, and might only require a small amount of additional coding. Perhaps one could choose between a "normal" character, with the game's current abilities; a "power hitter", who can generate slightly more acute angles, but either isn't as fast or gets tired more quickly; and a "retriever", who can't generate the same angles but doesn't slow down for a long time and/or who runs just a bit faster. Having three character options would mean a total of 18 variations (nine for 1P vs. COM, and nine for 1P vs. 2P) available via the Select switch, which isn't too shabby or ambitious.
  

Let me add that I don't have the ASM skills to pull any of this off, so this is intended merely as a proposal in case any of our resident gurus find the idea interesting. But unless I'm way off, I think most of this could be possible without a massive code rewrite, and could well fit inside an expanded 4K ROM. Of course, I don't know whether Tennis is already pushing the envelope in terms of available RAM, but given the Home Vision hack above, I'm guessing it's not.

 

What do folks think?

Edited October 14, 2009 by thegoldenband

[+thegoldenband]

Well, let's start with the first step: does a commented disassembly of Tennis exist?