Highly recommended. Very addictive.
I was coming to recommend this one too actually. It was my favorite demo from last next-fest by a long way, and the full version released yesterday. I've put in about 13 hours since then, so thumbs up from me.
It's a crazy mashup of breakout, vampire survivors and darkest dungeon - the combat itself is the brick-breaking breakout style, with the twist that you are using a specific RPG-like character that's literally throwing balls at walls of (mostly) static zombies that are slowly advancing toward you.
You get different 'balls' ( includes things like lasers and shurikens ) that level up and can be combined together or evolved into stronger versions. This is vampire survivors style with picking them from a random assortment each level up. There's an extra meta-progression layer in that the hero you use gets experience based on how you do on the run, that levels them up, increasing base stats that do things like letting you control more balls at once, run faster, etc.
There are 15 different heroes, each of which has different stats, but also some particular gimmick - for example, one of the first ones you get, the Sheriff, has autofire forced on, and built-in inaccuracy in aiming, but in return can fire at full speed while running, and shoots twice as fast as standard. Some of the later ones get pretty bizarre, like having the balls being fired from the top of the screen, getting a huge shield that supercharges stuff, basically turning it more like pong, or having the game play in turn based mode.
Between combat runs ( max 15 min, higher difficulty shortens the run ) there is a farming/base building element where you clear out space and build buildings, farms etc. An amusing twist here is that constructing and harvesting works kind of like combat, where you have your unlocked heroes and aim them at stuff and watch them run around and bounce off things to build/harvest them. Sounds stupid, but it's oddly fun, and adds an extra element to the base building tetris, where you need to consider how they are going to bounce through your town.
It's cheap, and has one of the most generous demos I have encountered - and any demo progress is imported into the full game if you decide you like it.