This little game is incredibly addictive! :D Graphics, SFX and overall presentation feel very slick and polished.
One minor thing that confused me on my first run is that friends that are alive after all enemies are killed can not be collected. I understand that this is probably done because of balancing reasons but it felt a bit weird and illogical.
Otherwise, this game is a gem. I can see myself playing it whenever I have a few minutes to spare.