Couple of major issues:
*No saving. If I hit clear, I'm back to 1-1(I've only tried this while on world 1)
*Incomplete rendering in some areas. Sonic may spend 1/8 the time half invisible sometimes.
*Is Sonic supposed to only lose rings if hit? Because it's kind of easy to get just 1 ring and be invulnerable to another hit, but if you have 1000, it makes no difference compared to 1.
And a question:
*Do you intend to also add in Tails?
Other than that, good job!

1. If you ever want to return to the level where you last left off, hold the left key as the SEGA splash screen fades to black. Instead of entering UGZ Act 1, you'll instead end up at a level select menu.

You can choose any level with the up and down keys, and select one with 2nd. If you want to guarantee that you get the good ending, press Alpha instead.

2. The sprite flickering was fixed in Version 1.00. However, said fix isn't in sonic2-fast.zip.

3. That's a feature in every single Sonic game. I don't know what else to tell you.

4. I could add Tails the same way I added the Spin Dash, by inserting the stuff added by other people's ROM hacks, but the one that adds Tails is closed-source, and besides, it overlays Tails' sprites on top of Sonic's, so it's pretty much a no-go if you want both of them playable.

Anyways, thanks for playing!

I still have flickering and when i exit the game I get a RAM Cleared (I used the full version, not the fast one). I am running OS 5.3.0.0037 on pre-A hardware. I had the same thing happen on my Python model, though.

I only have a Python Edition running on OS 5.6 from 2020, so I'm unable to test on the original model calculators. Until I can find out what's going wrong with my fix for sprite flickering, I've reverted some of the changes made for Version 1.00.

Sorry about that!

I have 5.8, yeah, there is flickering (Python edition.) There also is a graphic bug with the tiles and I can't enter level select.
Edit: Wait until before the Title Screen to press left.

is there any chance you can make a TI Nspire CX port of this? if you can, Dm me on discord at dominator11_

The Nspire isn't Z80-based so a direct port isn't really viable. Have you tried a Sega Master System emulator?

i cant use SMS emulators, since i was stupid and updated my Nspire to 4.5.5, so NDless doesn't have a version for that yet. I can only load LUA games, but there is an Assembly to LUA converter out there, so maybe that would work.

If you can find a LUA sms emulator then i could load it

From the description of version 1.00 improvements compared to the 1.00 upload I have on my two CE calcs I had the impression that the wrong build was released as 1.00 by accident, because the game flickering looks exactly like in the last screenshot. Could this be the issue?

yo is it posssible to make a port of this to the TI Nspire CX (non Ndless)? Like with LUA?

My "fix" for sprite flickering involved timing the LCD to 30hz. That seemed to work perfectly fine at first, but on real hardware, it didn't work at all and even froze the OS after exiting on my end. Because of that, I ended up replacing the Version 1.00 build on GitHub with one that's timed back to 60hz.

An unrelated fix that relied on 30hz timing made the flickering even worse on 60hz, so that was also reverted.


No. If you want to have a Lua-based Sonic experience on the Nspire, you'd be better off building a Sonic engine from scratch using Sonic Retro's Physics Guide as a reference.

I tried the latest release from github, but when I tried to play it, it showed the sega screen, then the sonic screen, & then went black & stayed black.

Were all of the appvars uploaded successfully?

I don't know, I used https://ticalc.link/

With the work you've done on this, do you think that porting Sonic 1 game gear as well would be relatively easy?

It probably would be if there was a full disassembly of the game. Without one, it'd be a pain to change anything about the game at all, let alone porting it to the 84+ CE.

Hey, everyone.

I made a write-up on all the methods I used to get 8-bit Sonic 2 running on the CE. It's the first time I've done something like this, so any feedback is appreciated.
Thanks for all the support!

Thanks for sharing the write-up! You hit a good level of detail vs. consumability, and provided a reasonable amount of background for an audience that is technical but might not know about our favorite graphing calculators' hardware specifically. I wish more people would create write-ups like this.

I do remain curious if there's a better way to handle ROM banking, especially since it would have been so easy on the z80 calculators. Has this already been discussed on Cemetech?