Really interesting concept! Easily the most creative way around the limitation I've seen so far. I love that the ice block slid around, but I was expecting it to make me slide much more. I ended up with a score of 1652 and there only seemed to be force from the block sliding at the very end, and it seemed to be inconsistent with the direction the block was sliding in... When the block slide down and left, the penguin slid directly to the right relative to the block, instead of sliding up and to the right.
I think the difficulty started too low and ramped slowly, so I had to come back to it after reading the comments to even realize there was any force from the block sliding around at all. I think it'd be nice if the difficulty started higher and then maybe ramped a little slower to compensate or something.