Had a lot of fun with this! Though I'm just gonna say you win by leaving two tiles on the screen instead of one, for my egos sake!

EDIT
Never mind, finally got my first win. One of my faveourte games so far.

Hmm, pretty tough but it does feel acheivable?

Thanks for playing my game, guys!
It is doable, and I'd like to believe that it's almost always doable. :)
Someone even made a solver for my game in JS. In case you are interested: https://gist.github.com/bojidar-bg/1142c341be5bdd1a9117fcd6e6f85ae9

This is an excellent puzzle game! It feels beatable every time, but also complex enough that I often make mistakes. I also appreciate the mouse controls, because it makes actions much more direct, so you can focus on the puzzle itself.

A couple tiny things I wish were here are a reset button (for when you know you really messed up), and maybe an option to undo the previous move? But other than that, this is nicely polished and fun. Really great work!