Serious Sam 3 might look way better than previous games in the series, but it's still Serious Sam through and through.
Serious Sam 3: BFE is still in alpha, but publisher Devolver brought a sweet demo of the game to E3 anyway. Basically, Serious Sam 3 is an incredibly gorgeous version of the previous Serious Sam titles with new enemies, new attacks, tweaked/new weapons, and destructible environments. Story-wise, it's a prequel to the entire franchise.
Serious Sam has always looked good thanks to Croteam's underlying tech, and Serious Sam 3 is no different. I was shown both a ruined city environment and a desert, and both were as detailed as can be. This includes the game's effects, with sandstorms in the desert that blocked Sam's view of advancing enemies and reflective oases.
If enemies get in close, Sam will be far from powerless at melee range this time. The new sledge hammer not only bashes in skulls with ease, but can perform a spin attack to take out all nearby foes. If the sledge isn't handy, or you just want to get your hands dirty, Sam has new melee attacks specific to each enemy. One features Sam pulling the eyeball out of a cyclops monster, while another features him ripping off a rocket-launching ogre's face. There's lots of over-the-top killing in Serious Sam 3, and I wouldn't have it any other way.
Many of the game's weapons will be familiar, such as the shotguns (of single and double barrel variety), the rocket launcher, the pistol, the chaingun, and the powerful-as-hell cannon. There are some new additions like the tweaked assault rifle and the shotgun with explosive rounds. I wasn't shown the entire weapon selection, but those that I experienced worked pretty well. It felt great to rip through hordes of enemies with the chain gun while still getting hit in the back by kamikazes I didn't think about despite their incredibly noticeable screams.
Calling Serious Sam 3 hectic is like calling a time machine neat. Enemies begin to pop up before you know it, and if you move on before killing all of them you only have more on your plate. This is what Serious Sam has always been, and it's what it still is with Serious Sam 3. The big difference is that even while behind four walls in Serious Sam 3, you're not safe. Werebulls will smash right through the bricks this time if you're in a destructible building. There won't be many places to hide from the enemy hordes. You can also smash through destructible objects with the sledge hammer, or cause the environment to crumble in the process of blowing up kamikaze soldiers.
If you don't want to go it alone, Serious Sam 3 is going to feature up to 16-player co-op through the single-player storyline. Enemies will scale depending on how many players get involved, leading to what Devolver called "total chaos" at the highest level. I don't think this is PR talk, as Serious Sam 3 already features quite a lot of enemies.
Serious Sam 3: BFE will launch on the PC as a digital download, and will come to consoles later. It's not currently planned for a brick-and-mortar retail release.