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Hey all, this is my first ROM hack.

On Ninja Gaiden for the SMS, the original ROM, once you reach 999 magic/weapon points, you can use the secondary attack infinitely without spending magic points. This can be done still early in the game, and simply makes the game too easy, specially because there is one of this attacks that makes you invincible and still causes damage to enemies.

I found out that the memory address 0xDFBB, which is normally 0, will be set to 0xFF when 999 is reached. This is used to avoid incrementing it more, but also at 0x50DF it is used to skip the routine that decrements the magic points when the secondary attack is used.
I patched this check to instead set 0xDFBB to 0 again and continue to the code that decrements the points.

One curious side effect, the points are normally a multiple of 5 until it reaches 999, after that, when it decreases, the less significant digit of the points will always be 9 or 4, but I tested depleting the points and collecting 999 again without any side effects.

The patch is attached.

Ninja-Gaiden-Europe-avoid-infinite-magic.zip (264 B)

That's great. I suppose this can be used with the prototype version too? I prefer that to the final release because of the much more fleshed out cutscene script.

Wesker wrote

That's great. I suppose this can be used with the prototype version too? I prefer that to the final release because of the much more fleshed out cutscene script.

Hello, I am not aware of this prototype, do you know where I can find it?

When we originally released the first dump (september 1999) we also had a prototype with it (at the time we didn't know it was a prototype):
https://www.smspower.org/db/ngaiden.htm

Emu-france normally has our download mirrors but weirdly can't find that ngaiden.zip from it:
http://smspower.emu-france.info/

CRC 1b1d8cc2 is final rom
CRC 761e9396 is the prototype rom
Should be widely available.

dellagustin wrote

This is used to avoid incrementing it more, but also at 0x50DF it is used to skip the routine that decrements the magic points when the secondary attack is used.

Wait, does that mean it's actually intentional? The latter seems to suggest that.

Kagesan wrote

dellagustin wrote

This is used to avoid incrementing it more, but also at 0x50DF it is used to skip the routine that decrements the magic points when the secondary attack is used.

Wait, does that mean it's actually intentional? The latter seems to suggest that.

It seems so, but maybe it was a testing left over... who knows...

Wesker wrote

That's great. I suppose this can be used with the prototype version too?

I created a new patch for the prototype.

Ninja-Gaiden-Europe-prototype-avoid-infinite-magic.zip (284 B)

Author	Message
dellagustin Joined: 18 Apr 2021 Posts: 6	SMS Ninja Gaiden Hack - Avoiding the infinite magic points Posted: Sun Apr 18, 2021 8:53 pm
dellagustin Joined: 18 Apr 2021 Posts: 6	Hey all, this is my first ROM hack. On Ninja Gaiden for the SMS, the original ROM, once you reach 999 magic/weapon points, you can use the secondary attack infinitely without spending magic points. This can be done still early in the game, and simply makes the game too easy, specially because there is one of this attacks that makes you invincible and still causes damage to enemies. I found out that the memory address 0xDFBB, which is normally 0, will be set to 0xFF when 999 is reached. This is used to avoid incrementing it more, but also at 0x50DF it is used to skip the routine that decrements the magic points when the secondary attack is used. I patched this check to instead set 0xDFBB to 0 again and continue to the code that decrements the points. One curious side effect, the points are normally a multiple of 5 until it reaches 999, after that, when it decreases, the less significant digit of the points will always be 9 or 4, but I tested depleting the points and collecting 999 again without any side effects. The patch is attached. Ninja-Gaiden-Europe-avoid-infinite-magic.zip (264 B)

Wesker Joined: 14 Jul 2008 Posts: 157	Posted: Tue Apr 20, 2021 12:00 pm
Wesker Joined: 14 Jul 2008 Posts: 157	That's great. I suppose this can be used with the prototype version too? I prefer that to the final release because of the much more fleshed out cutscene script.

dellagustin Joined: 18 Apr 2021 Posts: 6	Posted: Tue Apr 20, 2021 7:49 pm
dellagustin Joined: 18 Apr 2021 Posts: 6	Wesker wrote That's great. I suppose this can be used with the prototype version too? I prefer that to the final release because of the much more fleshed out cutscene script. Hello, I am not aware of this prototype, do you know where I can find it?

Bock Site Admin Joined: 08 Jul 2001 Posts: 8606 Location: Paris, France	Posted: Wed Apr 21, 2021 12:00 pm
	When we originally released the first dump (september 1999) we also had a prototype with it (at the time we didn't know it was a prototype): https://www.smspower.org/db/ngaiden.htm Emu-france normally has our download mirrors but weirdly can't find that ngaiden.zip from it: http://smspower.emu-france.info/ CRC 1b1d8cc2 is final rom CRC 761e9396 is the prototype rom Should be widely available.

Kagesan Joined: 01 Feb 2014 Posts: 821	Posted: Fri Apr 23, 2021 6:22 am
Kagesan Joined: 01 Feb 2014 Posts: 821	dellagustin wrote This is used to avoid incrementing it more, but also at 0x50DF it is used to skip the routine that decrements the magic points when the secondary attack is used. Wait, does that mean it's actually intentional? The latter seems to suggest that.

dellagustin Joined: 18 Apr 2021 Posts: 6	Posted: Sat Apr 24, 2021 3:42 pm
dellagustin Joined: 18 Apr 2021 Posts: 6	Kagesan wrote dellagustin wrote This is used to avoid incrementing it more, but also at 0x50DF it is used to skip the routine that decrements the magic points when the secondary attack is used. Wait, does that mean it's actually intentional? The latter seems to suggest that. It seems so, but maybe it was a testing left over... who knows... Wesker wrote That's great. I suppose this can be used with the prototype version too? I created a new patch for the prototype. Ninja-Gaiden-Europe-prototype-avoid-infinite-magic.zip (284 B)

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