Well hi everyone, I have been slowly trying to learn TI-nspire Lua here.
I have thought for a bit, made some demo beginner programs with the help of jimbauwens , and learnt a lot along the way (also creating a batch file for Luna for quick lua -> tns conversion). But I still have a long way to go.

So I had the tns file for 15puzzle but it didn't work, probably because it was designed to work with OS<3.0.2.

Fortunately I have managed to extract Problem1.xml from the tns file (rename it as a zip), copy to Notepad++ save as a .lua file, then used this page, to fix some errors/discrepancies with xml coding and tinspire Lua code, and got it working!
Played it, got it solved in 353 moves.

Now here I post the source code and tns file of 15Puzzle, edited by Jonius7 for OS 3.0.2 and above

And I think one of the best ways to learn is to analyse source code line by line and try to understand what it means.
So I shall try here with some help to dissect this source code:

function on.charIn(ch)
if ch == "r" then
board = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 }

-- Randomize
local swaps = 0
for i = 1, 16 do
local j = math.random(i, 16)
if i ~= j then
board[i], board[j] = board[j], board[i]
swaps = swaps + 1
end
if board[i] == 16 then
empty = i
end
end

-- If the number of swaps plus the number of empty-space movements is odd,
-- then the puzzle is impossible, so do an impossible move to make it possible
-- (exchange the space with a tile two squares away)
if (swaps + (empty - 1) + math.floor((empty - 1) / 4)) % 2 == 1 then
local i = (empty + 7) % 16 + 1
board[empty] = board[i]
empty = i
board[empty] = 16
end

moves = 0
platform.window:invalidate()
end
end

on.charIn("r")

function on.paint(gc)
local won = true
for i, n in ipairs(board) do
if n ~= 16 then
local x = (platform.window:width() - 128) / 2 + 32*((i - 1) % 4)
local y = (platform.window:height() - 128) / 2 + 32*math.floor((i - 1) / 4)
gc:drawRect(x, y, 30, 30)
gc:drawString(n, x + (30 - gc:getStringWidth(n)) / 2, y + 15, "middle")
end
won = (won and n == i)
end

local str = moves .. " moves"
gc:drawString(str, (platform.window:width() - gc:getStringWidth(str)) / 2, 0, "top")
if won then
str = "You win! Press R to reset"
gc:drawString(str, (platform.window:width() - gc:getStringWidth(str)) / 2, platform.window:height(), "bottom")
end
end

function on.arrowKey(key)
local dir
if key == "left" and empty % 4 ~= 0 then
dir = 1
elseif key == "right" and empty % 4 ~= 1 then
dir = -1
elseif key == "up" and empty <= 12 then
dir = 4
elseif key == "down" and empty > 4 then
dir = -4
else
return
end
board[empty] = board[empty + dir]
empty = empty + dir
board[empty] = 16
moves = moves + 1
platform.window:invalidate()
end


3.2 is not yet released ..
I think you are mixing version numbers

Here is a little list of versions:
3.0.0 -- Only on CX in shop
3.0.1
3.0.2 -- They added encryption to documents. Documents made with luna2tns and similar (for 3.0.1) don't work anymore
3.1    -- Present
3.2    -- Coming soon

Also, just to be clear, all .tns created with Luna work with all the versions

3.2 is not yet released ..
I think you are mixing version numbers

Here is a little list of versions:
3.0.0 -- Only on CX in shop
3.0.1
3.0.2 -- They added encryption to documents. Documents made with luna2tns and similar (for 3.0.1) don't work anymore
3.1    -- Present
3.2    -- Coming soon

There's a 3.0.0??

Anyway it would be great to check if all the cool old Lua games worked for newer OSes, and if someone could port them if the author left or doesn't plan to maintain them anymore. Also I guess this can be a good learning experience.

Well they sure didn't with Print for example . Had any old game used sound or stuff like that, sound would no longer work on OS 3.1 without Ndless.

And ok about OS 3.0.0, any difference with 3.0.1 in it such as no Boot2 crash?

Well I also meant about what it was missing from OS 3.0.1 or if it had any extra bugs.

For example I remember reading somewhere it still had leftovers from the 84+ emulator in the CX version, but I forgot if 3.0.1 still had those.

% Stands for modulo (though it can have other uses too)

a % b == a - math.floor(a/b)*b

About compatibility, DJ_O :

print() is gone in 3.1 (I haven't checked in 3.2 on-calc though).
gc:setAlpha() is gone in 3.2, and it wasn't documented before
on.create() become on.construction()

There is a retrocompatibility thing with platform.apilevel

So, the last one will be quite (on.create change) is probably the most annoying change, since it has to be updated...