Inspired in parts by Super Puzzle Fighter II Turbo and Puyo Puyo Tetris with its own unique spin on block-matching battles, Aloof has a demo up now.
What's interesting about Aloof, is that the blocks don't fall by themselves. You're not racing to find a position against a timer. You can move them down, to the side and back up to position them exactly where you want them. The developer said it's all about keeping up with your opponent, taking your time and thinking about what you're doing.
Available now so it's ready and waiting for the soon to arrive Steam Game Festival: Autumn Edition which begins on October 7. It's quite a fully featured demo too with single-player, online play which is cross-platform for Linux / macOS and Windows plus there's even local multiplayer too.
Once released in full they're planning to have a full solo / co-op campaign along with matches versus an AI player, special rescue mission levels and boss battles too. From my own time spent in the demo, it has an absolutely wonderful atmosphere and it's really quite charming. For a block-matching battler, it looks like it's going to be great.
You can try it out on Steam.