My lame ass discoveries

So we know that you can enter the level select codes in Sonic 2, swap the cartridge with Sonic 3 and presto- we have the codes for S3, yes? Good.

So what happens when we swap S3 with S2 after all that? Well, depending where the stage select was highlighted, the select will be in a certain location.
There are a total of 22 selections in S2 and 29 in S3.

So what the hell happens when we select something in the range of say 23-29? That's going to be what we are going to figure out. Note: this was first done on real hardware and then re-tested in kega.

For those who don't know how this swap trick works I shall explain:

First we lick our ROM for good luck and to join in the fads.


Then we turn her on and put in all the codes we need, level select and debug. Then we GENTLY pull out the cart while holding the A button. If the music is still playing but is messed up you're doing good. We then slowly insert the Sonic 3 cart. If the music is still playing it will sound different now. The sound does not need to be playing still for this to work but it is a good indicator that we haven't fucked up.

Do a soft reset and S3 should start up. If it does not then reload S2 and try it again. If it does work pressing up should bring up the S3 sound test. Enter it and then you should see the level select screen.


Now if we highlight say AIZ Act 1 and swap back to S2 it would highlight EHZ Act 1 and correspondingly to the 2nd set of 2P VS Act 2 being the sound test in S2 (Both being the 22nd choice) So if we highlight say, the 3rd set of 2P VS Act 1 and swap back to S2 what do we get in the level select? Well...

http://i42.photobucket.com/albums/e313/Wemes/Pic035.jpg
Holy shit it's the HPZ icon!
Notice that there's nothing highlighted on the screen.
http://i42.photobucket.com/albums/e313/Wemes/Pic034.jpg

Presing up or down will cause the select to go back to highlighting EHZ:A1 but what happens when we just press start?
Well we get this shit...
http://i42.photobucket.com/albums/e313/Wemes/Pic036.jpg
Notice this little blip in the screen in the lower right part of the title screen.
http://i42.photobucket.com/albums/e313/Wemes/Pic038.jpg
It also plays the music to Metropolis Zone and hangs at the screen.

Moving on, back in S3 if we move down a notch and go back to S2, the select icon shows CNZ. Pressing start causes this to come up.
http://i42.photobucket.com/albums/e313/Wem...333061_3300.jpg
This plays the music EHZ:2P and also hangs.

Moving along, selecting Bonus:1 in S3 brings up the HPZ icon in S2 and starting that brings up this...
http://i42.photobucket.com/albums/e313/Wem...896389_3300.jpg
Pure garbage with no music and also hangs at this screen.

Bonus 2 brings up this messed up icon...
http://i42.photobucket.com/albums/e313/Wem...185925_3300.jpg
And pressing start to this brings us back to the sega logo.

Down to Special Stage:1, we get a HPZ icon and pressing start brings us this...
http://i42.photobucket.com/albums/e313/Wem...297541_3300.jpg

And SS:2 gives us a CNZ icon and pressing start does absolutely nothing.

As does the sound test selection, it gives us an OOZ icon and pressing start does absolutely nothing.

That's it for real hardware, now does anything happen diffrently in emulation?

To emulate this all we have to do is make a S2 state with level select and debug enabled and load the state with S3. Then do a soft reset (ctrl+tab in kega) and go to the sound test. Then make states where each of the levels in question are selected and load each of them in S2. Do another soft reset and get into the S2 level select.

Differences to note: when we have highlighted the 3rd 2PVS:1 and load it in S2 the EHZ title comes up with its blip but then we get a messed up SCZ and if left alone we hear a monitor break and it goes streight to WFZ. Quickly turing on debug before this happens lets us see something like this
http://i42.photobucket.com/albums/e313/Wemes/sonic2swap1.jpg

SS2 lets us play a messed up version of EHZ:A1
http://i42.photobucket.com/albums/e313/Wemes/sonic2swap2.jpg
the level plays normal up to a point close to the end where it plays the boss music we see 'something' fly down but after it "lands" below us (where we can't get to without debug) there's nothing there.

Well that's it for what I have found. Is there a point? I dunno, maybe? If someone wants to take this further I'll be happy to help. If this has been covered before I would feel kinda stupid, but after searching I found nothing like this and I had fun with it, so I don't feel my time was wasted too much.

So take this how you will. You can say it's a great discovery of absolutly nothing, or you can tell me to SHUT UP and that NOBODY CARES.

 

Thanks for the support. I know how it can be around here when presenting something technical. (oh that's already known, blah blah blah) And you may not believe me but I first figured this out about 5-6 years ago back when I was a loser without internet. I didn't get everything back then, just one of the picks that gave the HPZ icon and the black screen with garbage. You have no idea what kind of thrill it was to find this thing just sitting in the final, and then figure out it just makes the game crash :-P (I don't think I knew about the beta back then or at least never played it. I didn't get to experience that till a few months later when I got internet) It's funny though because I remember swapping carts being much easier back then. Heh, maybe it's the hardware getting old or maybe just me getting old.

I must say though it was fun spending a day with it and a great way to reunite me with my genny (I think it was QJimbo that said something like ripping carts out of it wasn't the best way to reunite with it )