It's a novel twist on space invaders. I really liked the dynamic of choosing what additional defenders will spawn in the next stage, really adds some strategic depth to the game. One addition you might want to consider is a timer for a score multiplier, the faster you land the higher the score. This will give players incentive to play riskier for a higher score rather than wait for an ideal opening between bullets. The art and aesthetics are great and on point! Awesome job!