Anybody have any idea how to get this one? I'm only missing that and the one for finishing sequence.
Sidenote, this game rocks my socks.

In the sequence mode you need to make a smiley face out of the blocks of 5x4, by failing those levels, yet still completing the game.
Your screen will look something like this ( X's are completed levels, O's are failed levels)

X O X O X
X X X X X
O X X X O
X O O O X

Ah thats what that one meant . Thanks for the clear up .

"In the sequence mode you need to make a smiley face out of the blocks of 5x4, by failing those levels, yet still completing the game.
Your screen will look something like this ( X's are completed levels, O's are failed levels)

X O X O X
X X X X X
O X X X O
X O O O X"

Thanks. I was wondering about this one too. 

Has anyone actually managed this yet?

 It's pretty damn tough. I keep getting so far with the pattern then end up dying and messing it up.

By far the hardest achievement in the game.

You know, even in the demo, I thought it had something to do with Waves, but I couldn't be sure.

Ridiculously difficult.  I've come 2 short.

That is crazy tough. Its the only one I'm missing now.

I just got it. It took a bit of practice but I finally did it. :D

There is a useful guide located here which gives good tips and strategies for doing it.

Haha, this achievement is pretty clever.

I haven't tried for it yet, but I can imagine it's going to be a royal pain in my ass.

For the "eyes" you need to run out of time, not die.  So kill everything except a couple enemies.

This is the only achievement I don't have. It's extremely tricky, because any mistake results is fail. I tried for hours, no results. :(

hmm, i really wonder if devs just pick a week to sit down and think about stupid but awesome achievements

Good video guide here.