I do have a recommendation about a game like a zombie game, where you shoot zombies, in a square-ish area. As rounds passed the zombies gets harder and harder to kill and every 5 rounds there is a boss. After defeating the final boss you will get an ending based on your actions during the game. There is also a shop where you can upgrade your guns , hiring teammates, buying medkits and such. I hope u found my comment interesting and I am sorry if my recommendation is hard to make. I understand if you don't want to make this.