First of all, thank you so much for playing the game and for your honest feedback!
The reason for the repetitive buildings is that there aren't many well-optimized building assets available on the marketplace, and I also had a very limited amount of time to complete the game. So, instead of spending too much time creating or searching for models, I decided to focus that time on building the game mechanics.
As for the lag, my PC doesn't have a dedicated graphics card. It only has an integrated Intel UHD GPU. Somehow, I still managed to complete the entire game while working in a very laggy editor!
I'm really sorry about the performance issues. Hopefully, in the future, when I'm successful enough to purchase a proper GPU, I'll be able to create something much bigger and better than this with better optimization.
Also, if you'd like to play my future games, feel free to follow me! Just a recommendation 😁