Great game! Really struggled to survive though (may just be a skill issue). I couldn't get past the fourth wave on the first level, despite trying several times. Would hope for an option to retry from that specific wave instead of beginning from the beginning. Although I did not get to try the other levels, I still enjoyed the game.
EDIT: Haver showed me the gameplay of the game so I watched it and wow. The gameplay has a lot of depth. The presentation of the different visuals look cool and I loved how the gameplay changed throughout the game. Excellent submission for the theme of simpler times :D