Impressive amount of work on the graphical front. The 3d models looked great especially for a week long jam. It took me a minute to realize you needed to match the ammo with the zombie color. I kept shooting thinking I was doing damage. It would be nice to have some feedback when the ammo is ineffective. I also got into situations when the ammo color I needed didn't spawn and had to collect ammo and move around the map until it did.
The first time I played a zombie pushed me out of bounds and I fell off the map. It also seems like they only do damage when they first collide with you. Enemies also get stuck on the objects on the map making it not very challenging. Despite all the issues, it was an impressive amount of work for a week and good basis for a wave based shooter. Fit the theme well too. Great work!