1. The bullets can be in a different shape and so is all the zombie and player or maps and even wave complete and lastly heart lives especially particles. 2. No sus ones. 3. It can be in other concepts base of a different game in scratch or not in scratch. 4. You can make it cartoony or even make it yourself. 5. No stealing from a concept that looks better then yours.
I also wanted you guys to make your own concept. Also please show me when your done.