I can confirm it does not quite follow the rules. In my game it castled to escape a check, which is forbidden.

That sounds a lot like playing any game with a young child. The difference is you can't correct a game-playing AI when it doesn't follow the rules.

So in a way it's a lot like playing a game with a young child after you've stopped caring about the rules.

I'd find it more enjoyable if I could remember what pieces the abstract shapes represent.

They're reasonably evocative (both of the pieces' actual nature and of the traditional shapes used for them), I think.

The rook/castle, which moves orthogonally, is represented by a square made out of orthogonal lines.

The bishop, which moves diagonally and traditionally has a kinda-triangular mitre on its head, is represented by a triangle with diagonal lines for sides.

The knight, which moves in a funny way and is traditionally shown as a sort of horse's head, is represented by a quarter-circle which is unlike all the other shapes (less symmetrical, mix of straight and curved lines) and actually quite similar in outline to the traditional horse's head.

The king, which is usually shown with a cross on its head, is represented by a cross.

The queen, which moves like a king but more so and which is usually shown with a many-pointed crown on its head, is represented by a many-pointed star (a bit like that crown, and also a bit like the king only more so).

And the pawns, which are weaker than all the other pieces and traditionally smaller than the others, are represented by little circles, smaller than the other pieces.

I just hung a piece to the opponent's knight because I didn't realize it was a knight.

Its completely unplayable for me.

it's like you are explaining how somebody can invent a new alphabet that is "evocative" so we should accept using it instead of the alphabet we already know.

or to put it another way, Staunton.

You can get a checkmate in 5 moves: http://imgur.com/E5XTouu

I'm pretty sure this is quite old. I remember the exact same graphics from something I played with at least 12 years ago (I think it might have actually been in like 2001 or 2002, but my memory is vague).

Multiple people on /r/chess are saying it also castles its way out of check (which is, of course, also illegal).