nice job so far! it looks great! i do offer myself up as your humble guinea pig. also, no. im doing pokemon, and 250 bytes is enough for half an attack effect. if you can fit a mechanic so necessary in that much space, then go for it. optimize as you can, if you wish.

can i see that particular code? or is that against your moral fibre?

Since there is tile-induced movement with varying dominance over user input I calculate the direction/change in position and leave determining if the new spot can be moved to to another subprogram, currently 283 bytes and I'm estimating another 200 bytes after I implement switches.

N=tile currently on
D=direction (-1=left, 1=right, -.01=up, .01=down)
L3(6)=ice skates yes/no
L3(7)=suction boots yes/no
K=key press (using xLIB's getKey)

N between 21 and 25 are ice tiles, so '2<abs(N-23' is true when it's not an ice tile.
If you land on a regular ice tile (N=21) you continue in the direction you stepped on it.  The others are curved and redirect you depending on how you come at it.  My name for them is "ice NW/NE/SW/SE" depending on the corner it's in.  For ice NW: if your direction is 'up' it changes it to 'right', if your direction is 'left' it changes to 'down',  and so on for NE/SW/SE.

N between 17 and 20 are force tiles.  They push you in a certain direction, but you have limited control over Chip (you can move off to the side, but not directly against how their pushing you).  20=right, 19=left, 18=down, 17=up

Here's the code for determining 'D'.  I have the 'If:Then:End' statement to increase speed even though they're adding about 10 bytes (I did speed tests to confirm they help).  It's only 164 bytes now, but I'm estimating another 90-100 bytes for when I add in the semi-bordered floors and switch tiles.
:If L3(6) or 2<abs(N-23:Then
:(K=3)-(K=2)+E-2((K=1)-(K=4→D
:If not(L3(7
:D+(N=20)-(N=19)+E-2((N=18)-(N=17→D
:Else:ND
:D+1.01((Ans=-.22 or Ans=-22)-(Ans=.25 or Ans=25))+.99((Ans=-24 or Ans=.24)-(Ans=23 or Ans=-.23→D
:End(E-2 is the little E to the -2 power, ie .01)

Enjoy

P.S. Sorry if I sound like I'm bragging. >_<
I actually just want to help.

Nyaar is an accomplishment that deserves to be bragged about!

(EDIT2: Now that I think of it... I wouldn't know how to implement moving enemies into this system. Well, I have an idea... but I don't feel like testing it out.)

Why did you have to remind me the enemies are moving.  I've had such a good day so far .  It's gonna be a freakin' pain, and there are at least 5 levels I might have to leave out because the massive number of enemies to keep track of would probably make the calculator shoot sparks and explode :boom: (that's another smiley we're missing, the exploding one)

Direction is nothing I ever needed to (or wanted to) bother with.

Once you get the hang of it it's pretty simple (although getting the hang of it is the hard part).  I had to try about 4 different ways to group the tests to get that last little 76 byte gem (it starts 'D=1.01...').  There is a tiny little bug, which could potentially give someone a small advantage, that would require a complete rewrite of the code in the program that determines if the tile can be moved onto as well as cause a major speed loss, so I already have my first nearly useless easter egg.

[edit] @{AP}: What is your avatar?  Is that a whale flying in and landing on/squishing a little puppy?

It's supposed to be a seal.
Though, yes... it's doing what it looks like it's doing.

Explanation:
http://www.newgrounds.com/portal/view/435047

wow looks nice so far, tiles looks pretty sweet, keep up the good work!

Maybe with a mask it can be better (just xor it before put the sprite) :



Or I think xor a white square before xor the sprite will have the same effect.