I get what the Serious Sam games are going for, but you need more than just a massive fuckload of enemies on the screen to be a fun FPS. I've tried getting through this, but it gets boring after a few levels when you realize it's literally nothing but killing waves of enemies. It's about the same thing as opening up gm_flatgrass in Garry's Mod and spawning a bunch of fast zombies. At least in Garry's Mod the weapons actually feel good to use.