Go Mecha Ball is by far the coolest Steam Next Fest demo I've played so far, and I can't recommend it enough. A top-down, twin-stick shooter where you can turn into a giant mecha wrecking ball that bounces around the tight playspaces while shooting at enemies, Go Mecha Ball is a fast-paced roguelike that genuinely had me upset when I got to the end of the demo. It's a little bit Super Monkey Ball and has the bright bouncy play of something like Rocket League, it's great.