Serious Sam 4: Planet Badass [Official Site] from Croteam has me rather excited, it also has more information out and some fresh screenshots. Click the shots to make them bigger.
Firstly, they're saying it's going to be a much bigger game with "huge environments populated with optional objectives, secrets and deadly ambushes". To be clear though, they do say it's not an open-world game, but the same linear experience as before. There will be plenty to shoot of course, with practically everything trying to kill you.
They've also now confirmed that the motorbike shown in the teaser trailer is actually something you will use. Not just that, they amusingly said you will be able to drive "a combine or even a bulletproof popemobile and drive your way through unfortunate enemy pedestrians".
On top of that, companions will be joining you directly in the game, not just cut-scenes. That sounds good, should be interesting for the co-op side of it!
Hopefully a proper trailer will be released soon!