Pros:

• Very simple gameplay. 
• Easy to understand

Cons:

• Crashing if just pressing ESCAPE, getting to the 3rd level and that's just from one playthrough. With 7 days level, this really should be happening
• Stretched assets. Very bad looking, You can fix this if you just make smaller cubes so textures aren't stretched.
• Better level design. I speedran level 1 and 2 in 2 minutes, and that include restarting twice cause of crashes.
• No main menu..... I spent about 5 minutes looking at a rotation cube and crashing a few times pressing ESCAPE. And when I figured out I had to press SPACE I had to read a hell lot of grammatically incorrect lore that had NOTHING to do with the game.
• Too many free assets. The enemy had nothing to do with the theme, the door is a sci-fi high-quality door in your stretched low-quality texture world. Don't really fit

Final words:

With this being made in only 7 days it's fine for a beginner (I guess you are). It's a clear concept which is very nice. Now you have 14 days, so you are expected to use all of them. So having a lot of crashes and bad level design really isn't anything you can blame on time pressure but on you being lazy. Also, I understand as a beginner you do use a lot of assets, but when you use them at least make them look like they match instead of these half-ass stretched pixel art wall textures mixed with high-quality zombie. I think you made an okay game, but you could have made it way better if you just spent a bit more time on it.