Straight 5's. Like KerBull Space Program, I don't think I've laughed so hard on this jam than the countdown hitting 0 to massive fanfare and the total cutout of music as my cow explodes. Mechanically the initial 10 seconds is both stressful and hilarious, and knowing I can't take the piece off once I've strapped the fuel tank above the thrusters on accident lead to some absolutely brilliant emergent gameplay. Being able to upgrade was just the cherry on the cake.
Easily one of the best entries by some margin.