Those are tons of zombies man! Just killed 350 until got push out the map, it was fun! Here's the things i saw that you could dig in, you can jump over them and they can't do nothing,, there's also zombies spawning on the top of the screen which is annoying in the long term.
That's really all! The game is very cool, and i could see a future full survival 2D zombie game here:)