Another way to create an intense gameplay is surely using sounds, but unfortunaly we're quite limited with the A7 engine when it comes to sound.+

But nevertheless, that would be a possibility; creating immersion by using sounds right, overdriving explosion and muzzle sounds...

And also, having as few panels as possible. Dead Space made a excellent job of that; For example, showing the player's health with some realtime panels on his armor.
The only bad thing is, for the guns. You have to have REALLY big guns to make sure the player can read the panels on them.