MZM Trivia

[FelixWright]

This is a thread to share various quirks about Zero Mission we as a community have discovered through hacking or playing the game. The idea is that a lot of it may come across as "Huh, neat" for now, but save headaches when hacking the game later. I'll start!

• the wall eyes (Sprite id# A6, A7) in chozodia cannot be killed until the chozo ghost (Charlie) has been defeated.
• There is a time attack mode accessible by selecting a completed() save file and pressing Up, Left, Right, Down on the DPAD. Time attack uses Normal difficulty, recording your best times as Any% and 100%, generating IDs and Passwords for each. If you beat your best time in either category, next to your final time on the end screen you will see "NEW RECORD."
• ZM calculates end percent by sticking all the item counts into a single number, which restricts super missiles and power bombs to 0xF (15) tanks max each.
• By using a door connected to crateria door 0 with the ship in the same room, the intro cutscene replays, you lose all your items, and you can't get them back.
• Kills with Screw Attack, Charge Attack, Speed Booster and Shinespark call for a different death AI which can break enemies such as Zebetites in Tourian, and Imago in Ridley. (Which causes a softlock)
• you can (pixel perfect) walljump off of slopes.
  https://youtu.be/Mggu6_49rGU
• the chozo mural (charlie) gives you varia suit for free and it counts as a % if you don't have it already
• bg1 is loaded with a bunch of random stuff while using a map station which you can see if you make any map tiles transparent.
  
• There is a fourth minimap color, but you don't see it because it looks exactly like the heat room color in vanilla. It is my personal belief that it was intended for heated secret rooms. You can see it by editing palette 4113E0. However it uses the heat room glow animations, so you have to use custom asm to give it its own animated palette.
  
• zero mission has anti-cheat for time attack in the form of its own "splits" in memory which checks:
  
  
  
  • if Kraid was killed less than 5 minutes into the game (stores to 3000184)
  • if MB was killed in under 10 minutes (stores to 3000188)
  • if full suit is obtained in under 16 minutes (stores to 300018C)
  • if mecha ridley is killed in under 22 minutes (stores to 3000190)
  it also checks if you have more than the intended number of items.
  if any of these are done out of order, it will also trigger anti-cheat measures.
  when triggered, anti-cheat blanks your time attack ID.
  

• The filler for tileset 38, used in Charlie/Chozo Ghost room, (Chozodia 2A) uses the same filler as brown doors, in the second row of Generic BG palette. (0x5DFE40)
  

[RT-55J]

For those of you who are curious about the anti-cheat stuff, it is (technically) possible to trigger it without cheating. Dragonfangs's TAS of the game finishes with an in-game time of 20:59. Note, however, that the best non-TAS in-game time is 24:58 by CScottyW, so a few frames or so need to be shaved off before a human crosses that barrier.

[Steel Sparkle]

some cool information!
Its always fun to learn new Metroid based info.

[FelixWright]

The filler for tileset 38, used in Charlie/Chozo Ghost room, (Chozodia 2A) uses the same filler as brown doors, in the second row of Generic BG palette. (0x5DFE40)

[ForgettablePyromaniac]

There's a door in that room to the right?

I haven't played the game in a while, but I always thought you had to space jump back up... Is it unused?

[spoiler]Also, since I'm here, why are there blocks that require power bombs in the regular part of the game cuz I swear I can't find a tank for them until the pirate ship. I'm probably just blind as hell, but I digress... (Either that or I'm misremembering terribly why I never got 100% lol)[/spoiler]

[LetsPlayNintendoITA]

There's a door in that room to the right?

I haven't played the game in a while, but I always thought you had to space jump back up... Is it unused?

[spoiler]Also, since I'm here, why are there blocks that require power bombs in the regular part of the game cuz I swear I can't find a tank for them until the pirate ship. I'm probably just blind as hell, but I digress... (Either that or I'm misremembering terribly why I never got 100% lol)[/spoiler]

you can come back to the regular part of the game after the ending

[ForgettablePyromaniac]

you can come back to the regular part of the game after the ending

WHAT

WHY DO I NOT KNOW THESE THINGS I FEEL STUPIDDDDDDD

now i need to look this up and reopen my copy on wiiu to try this ._ .

[FelixWright]

There's a door in that room to the right?

I haven't played the game in a while, but I always thought you had to space jump back up... Is it unused?

[spoiler]Also, since I'm here, why are there blocks that require power bombs in the regular part of the game cuz I swear I can't find a tank for them until the pirate ship. I'm probably just blind as hell, but I digress... (Either that or I'm misremembering terribly why I never got 100% lol)[/spoiler]

It's a one way door to fight the Spirit of the Mural.

you can come back to the regular part of the game after the ending

It doesn't have to be after the ending. All you have to do is go back to the tube connecting Chozodia to the Mothership. If you have played Super Metroid, you may know what you have to do next.

[ForgettablePyromaniac]

It doesn't have to be after the ending. All you have to do is go back to the tube connecting Chozodia to the Mothership. If you have played Super Metroid, you may know what you have to do next.

DUDE WHAT I'm learning a bunch about this game I used to play the hell outta. I gotta really 100% this at some point. I might, actually. If I get an afternoon where I'm not busy with my Doom moddin' and waddin'.

[FelixWright]

2x2 shot blocks are pretty cool.

Code Select Expand


53 - Top-left shot block (no reform)
54 - Top-right shot block (no reform)
63 - Bottom-left shot block (no reform)
64 - Bottom-right shot block (no reform)

50 - Top-left shot block (never reform)
51 - Top-right shot block (never reform)
60 - Bottom-left shot block (never reform)
61 - Bottom-right shot block (never reform)


Each block in the 2x2 square has the behavior of breaking the other three, so you don't need all four corners. They will also break other blocks and apply their "no reform"/"never reform" properties to them. For example, if you were to use "reform" bomb blocks on top and "no reform" 2x2 shot blocks on bottom, destroying the 2x2 shot blocks would prevent the bomb blocks from reforming until the room was reloaded. That said, the "no reform" and "never reform" properties from the 2x2 blocks do not work on "reform" blocks that are currently destroyed.

It gets weirder.

With "never reform" 2x2 shot blocks, if the top left corner is not clipdata 50 then only the top left corner breaks as "never reform." the other three blocks will reappear when the room is reloaded. However, if the top left corner is clipdata 50, even as the only "never reform" 2x2 shot block, none of the 2x2 square will come back. This even applies to "reform" blocks that should come back without leaving the room.

[FelixWright]

Stop enemy air blocks prevent bomb jumps. Additionally, if you morph on a frozen enemy while touching a stop enemy block, you fall through the enemy. This is a quirk of both Fusion and ZM.

https://youtu.be/0rtuPdS8CFY

[FelixWright]

Atomics are hard-coded to not spawn if the difficulty is set to Easy.

This can be fixed with an easy tweak: 0x803BCEE : 03 48 to 09 E0

[FelixWright]

You may have noticed that slopes always have solid blocks on either end of them:



Without solid blocks on slopes, crawling enemies clip out of bounds... and you can make "Coyote Bridges."



By running across slopes like this and not stopping, Samus can run on air. But as soon as she stops, she falls.

[FelixWright]

For almost everything, this is how ZM's areas are ordered:

• 0 - Brinstar
• 1 - Kraid
• 2 - Norfair
• 3 - Ridley
• 4 - Tourian
• 5 - Crateria
• 6 - Chozodia

In at least one particular case however, at the pause screen, when you switch through areas with SELECT, the order is:

• 5 - Crateria
• 0 - Brinstar
• 1 - Kraid
• 2 - Norfair
• 3 - Ridley
• 4 - Tourian
• 6 - Chozodia

While intuitive for players, as a hacker I can't unsee it! And it also makes tweaking the NG+ Per-Area item counters slightly more difficult.
So here's a tweak:

0x840d67c : 05 00 01 02 03 04 06 00 -> 00 01 02 03 04 05 06 00

[FelixWright]

Every suit has a unique palette for every situation, even if they might look identical.
You can edit them for fun things like unique per-suit damage colors.