ETK has posted this update on his site:

Today I have changed the collision engine (I didn't really like the other one)which fixes some bugs and improves the precision. Now the code is in more than 1 file, which makes it easier to read.

Since Collision engine is almost done, I have started the weapon/shots engine also and made a simple debugger which shows which sprite is available to use with the "new shot".

More info --> http://etk.scener.org/