I played around with it a little. There are some aspects of it that are frustratingly limited right now, such as not having very good methods to deploy the bombs and fireballs that are provided, and the cannons are strictly single-shot.
But it's clear that the game is in early development, and has a long way to go, so it will be interesting to see what it turns into. At the moment, it's enough to keep you occupied for an hour or so.