Well, after many attempts to actually release this, I finally have. Here are some interesting features, in case you are interested:

Download Portal Returns
::There are 78 total levels included; 40 in the main pack and 38 ported by Unicorn in a custom pack
::There may or may not be cake at the end
::A couple hidden buttons that do things; not really too interesting things though. But if you find them, neat.
::You can customize all colors and tiles and sprites in the game, except for the guy. I'm not going to let you change little elephant dude.
::Umm... Try it out and see what be a-happening. There's a ton of stuff... Like a lot.

And of course a screenshot:


A random level with a custom touch:


Note: As for the customization thing, it takes a bit of work at the current moment... I believe I will post a tutorial, or maybe write a program to do it. Probably will be computer-based though. What it does it use a separate AppVar and loads the custom data from it. So it is completely self-contained. This means you can make invisible things, if you really wanted too. Honestly, you can make it rainbow colored with flowers. But that is a separate thing; the game already supports everything. Maybe I'll post a demo one or something...

This means that you can make the game however you want. However, the effect only takes place in the main program; not the editor... Because of things.
So for example, you can make full fields with pink and blue portals, with a green dude in a yellow world...

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Once again, I would like to thank everyone here for their support and help along the way! It certainly took made it go that much faster. A special thanks to Unicorn, CKH4, JamesV, RalphWorthington74, and 123Outerme for extensive bug testing and advice. Press [2] on the homescreen to see some stuff.

Thank you Kerm and tr1p1ea and chickendude and others for the programming help along the way; and now I am glad to say that this program is complete! As long as no one stumbles across a bug that I missed, which could happen, I guess.

And now for the finishing smile:


And 5 months, 8 days later... Or 159 days.

Ooh nice! I'm sure this will be a major hit, good luck!

Hmm... This idea is becoming more and more difficult the more I think about it... Simply moving a player around a tile mapped screen and firing portals is one thing, and physics would not be too difficult, but it is the drawing that upsets me. Back on the monochrome calculators, XORing sprites and even copying the data behind them wasn't too bad, but now things get interesting. How to display only a portion of the character with flipping and masking. Well, I think that I may have spoken to soon, but I am going to need to think on this. It may be one of those things that takes a while...

I thought it would be challenging. Good luck

Since the character can't go behind anything that's not air, just draw it before the map. That way, when it's halfway through a portal, the map drawing will erase part of the character by itself, and you can just display the other half of the sprite the same way behind the second portal, and it will be half cut-off like the first part.

That only works if you redraw the map every frame, which is probably not a good idea on the CSE. Plus, you don't need to redraw the map each time since it mostly doesn't move so it would be a waste in my opinion to redraw it just to erase part of the character.

That is a good idea if I only draw the portal sprites, which was one of my original ideas, but then I realized that I would also have to take in to account that the sprite would have to sometimes be flipped and rotated, which takes some time to think about. It is by no means impossible, but it is not as easy as only rotating an 8 bit wide sprite. This will be interesting...

EDIT: Looks like BuilderBoy has released his source for the original portal; the only challenge will be learning Axe... Probably should have done that a long time ago.

EDIT: Hold up; after playing with the original for a while, it looks like Builderboy did not do sprite rotations. The player is always facing up... This is a good idea! Much easier now.

You don't need to redraw all of the map every frame, but only the 1-to-2 tiles that the character is on. Basically, display a white square to erase the player's sprite, then display the tiles that were partially or fully erased, if the tile is not a white square. That'll only take a small amount of time, as the player can't intersect with more than two walls (and only when he is halway through a portal).

Yep, that is what I have up there ^^. Now a question I have concerns bumping: how should I bump the portal to be correctly located?

In my opinion, make it 1.5 or 2 times the size of the character, in a way that the size of the portal is a multiple of a tile's size. That way, you can pretty much align portals with tiles.

This sounds amazing! Btw, mateo, did you try the level packs?
Will it also support levels from the monochrome?

Okay, here's an update:

-Figured out Half Res mode so that double buffing is a valid option
-Finished map tile loader
-Made some sprites

Screenshot:


This could take a while...

Woah! Looks amazing, I can't wait for this!

Holy cow. This looks amazing! I cant wait for the release!

Wait whaaaat?! Thats amazing! *Mindblown*

Thanks! This is definitely not going to be a quick program. Here is a little running sprite I made -- still have to deal with low resolution.

Looks good Will there be a walking sprite as well or just a running one?

I don't see the point, many platformers don't have a sprint button. On top of that, the original Portal doesn't have a sprint button either.

Whoa, great screenshots! Seeing this makes me want to get back to porting M-Game (N-Game) to the TI-84 Plus C Silver Edition, actually. If you want inspiration for running figures, you're welcome to check that project out. I notice that you made it an App rather than a program; was there any reason for that?

Okay, I really haven't been focusing on this much at all because of school, but here is a screen shot. Simple collisions are done, and can be varied to add portal collisions. This speed is about 1/70th of the fastest.