The Things Remaining: SMBX2b4


Some of the curious bugs among you must’ve noticed a little bit of a revamp happening to our To-Do list last week. As we move closer to release we decided to clearly distinguish between what’s necessary and what would be nice to have for the release, so that we can make decisions about what we might have to cut. It’s still a beta, so there will always be more opportunities, after all! But before I go into detail about those, I want to give a small update on the things happening.

The images in this post are largely unrelated to the texts below, I just figured it would be nice to have a couple things to look at in addition to words to read. They’re from various testing sessions, showcasing some fun interactions.


Over the past months, the main topic of the Imperfections and Interactions post was being worked on – checking the imperfections of all newly added elements and making sure they work. The vast majority of this work is now completed, meaning that when the update releases, you won’t run into a game-breaking error when trying to use a large number of new additions! Hooray!

The exception right now are interactions between new npcs and other new npcs which, while not game-breaking, are awaiting a piece of new tech which will likely not be ready for release (and would delay release by a couple more months). It’s something to be wary of, but nothing to be staying away from new npcs for.


Another feature that will likely not be quite ready for release is easy NPC editing. In the future, all new basegame NPCs will be loaded through “npc-id.lua” files, where “id” is the ID of the NPC. Changing the name of the file will be enough to create a duplicate of the NPC’s behaviour for local use! No more “unloading” shenanigans like with Beta 3! In addition to this, having a local copy of, say, npc-301.lua (Thwimp) will cause both the basegame file as well as the local file to apply their code in parallel! This means that you can mod the Thwimp without copying all of its code over by just making a file with the correct name.

I’m trying port as many NPCs to this system as possible for release, but there is a high chance it won’t be ready for all of them yet.


While most NPCs are ready, there are a few which still need some bugs ironed out. In particular, lineguided NPCs are the last NPC-related hurdle and are being worked on in parallel to all remaining issues.


A few things need a bit of a restructure in order to be more performant overall. You might have noticed in SMBX2b3 that new blocks in particular were very prone to slowdown when used in bulk. Stuff like that is something we will need to address sooner or later, and we want to take care of it sooner so that it doesn’t become a bottleneck that makes designing with these new tools unfun.


Beyond the biggest hurdle of “performance”, there are a couple minor errors remaining in included episodes, editor preferences or factual errors in our documents which we’re working on to resolve. Little stuff that shouldn’t take long to resolve but is still important to sort out.


We’re not yet confident that development can continue at a steady speed until release, so we don’t wanna pin anything down just yet. The moment we’re ready to share a release date, though, it will be immediately announced alongside a trailer and a new blog post. It’ll be impossible to miss!


17 Replies to “The Things Remaining: SMBX2b4”

  1. Now I’m really interested in SMBX2 beta 4 because a lot of stuff will be added to there and it would be a lot more elements compared to 38A’s SMBX 1.4.x!

  2. Me: I’m considering using 1.4.x for my episode. Change my mind
    Beta 4 blog post: *exists*
    Me: (0[]0)

    mInD cHaNgEd

  3. Based on some things, I wonder if the other character’s specific shots will be their own NPCs come beta 4 or beta 5… (Looking at Samus and Uncle Broadsword.) Still interesting on the work and process going.

    1. Broadsword’s boomerang is a new projectile already, since he won’t see much of a change in terms of his mechanic come beta 5. Other projectile-based characters are subject to review and will see NPCs for their projectiles in Beta 5!

    1. Being able to set flags from NPC config (npc-n.txt) that determine stuff like “how much damage would this npc id take from a samus missile?” or “can this npc bounce on springboards?” Currently this kinda stuff is hardcoded or would at least require a couple of lua lines to alter, and it’s cumbersome to work with.

  4. Will beta 4 have the complete graphics for each version of super mario bros? (SMB1 8-bit SMB2 SMB3 SMW NSMB ETC)

    Will it have new NPCs like Skewer, Shooting Clown Car, and Chain Chomp?

    Will it have abilities like Ground Pound, Twirl, Wall Jumps, etc?

    Will it let players wear shellmet and others?

  5. Wow, They adding the 1.4 scripted contents, even these NPCs from Teascripts. But if only i had patience to actually waiting for this…

    1. Please keep in mind that these NPCs are also in standard Mario games, and the fact that they’re also adopted into another Mario Fangame Engine is purely a coincidence.

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