I didn't run it like a typical 4e, and that's probably a reason why I enjoyed it so much. I focused on set piece battles instead of attrition combat and used Skill Challenges extensively
4e is pure action adventure in a way no other D&D can emulate!
So, to elaborate a bit on my response to Randomthoughts and what AbdulAlhazed has said: here's a summary of the first action sequence I ever ran in 4e (Jan or perhaps eary Feb 2009), largely cut-and-pasted from another recent 4e thread:
The first combat that I ran in 4e was the river ambush from Night's Dark Terror. I wrote up a group of foes - a reaver (3rd level human guard from the MM), a mage (2nd level human from the MM), a halfing (1st level slinger from the MM), a backstabber (a dagger-using variant of the 2nd level human bandit from the MM) and 10 1st level minions - some slingers, some stabbers - adapted from the MM human rabble. That was 750 XP worth of enemies.
I drew up a pretty simple map of a short stretch of river on an old (as in, acquired some time in the 1980s) piece of graph paper, with banks at either end a bit over 20 sq apart, a sandbar in the middle, with a tree at one end, and a sketch of the starting point of the PCs' boat (about 2 sq x 4 sq, plus some bits to squeeze into at the ends) and a raft (3 sq x 1 sq) by the bank for the bad guys. The bad guys' bank was wooded.
I had notes on the concealment provided by the woods, and the muddy terrain of the river banks (difficult, and also steep on the side opposite the bad guys and so requiring DC 10 Athletics to get up). I also had notes on the cover provided to the PCs by their boat, the Acrobatics DC (10) to stand in it, and the skill challenge needed to disentangle the boat from the chain that the ambushers use to stop it. This included a note that every dead minion is a skill challenge success (because they're the ones making sure the PCs don't interfere with the chain).
Given I ran this encounter 11 years ago my memory isn't perfect. But I have memories of PCs trying to jump from the boat (where they were sitting ducks for the slingers) to the sandbar. Some ended up in the water. The mage and reaver left the bank on the raft so that they could attack the PCs, and a group of minions also swam out. When I looked through my old notes they showed that, at one stage, the PC wizard was alone on the boat, the paladin was struggling through the water to the sandbar, the warlock was on the sandbar taking cover behind the tree, and the fighter was in hand-to-hand with e NPC reaver. I remember that the fighter won that fight, as that was where he acquired his Black Peak halberd, which was his specialty weapon until he reforged the Dwarven thrower Whelm into the mordenkrad Overwhelm.
I also remember that the encounter was difficult. The players found the terrain punishing at first, being stuck on a boat and only the fighter having Athletics training to swim to the sandbar - but being a dwarf and so fairly slow. The PCs were suffering hurt from the enemy slingers with their 20 sq range.
But it's pretty well-known that 4e delivers a reliable "heroic rally" for the PCs, and that must have happened here because the PCs prevailed in the end. The notes I found have the paladin having used one Lay on Hands plus his 1x/day multi-class Inspiring Word. I can't remember everything about the way this situation played out, but I do remember that the PCs took control of the raft, and took the NPC mage prisoner. (A couple of sessions later she got turned into a wight by a goblin shaman's necromantic magic.)
I don't think I could have designed this encounter without the advice from the DMG on how to use terrain and to integrate it with the enemy forces. The idea for the raft came from reading the vehicle chapter in Adventurer's Vault. And the mechanics were crucial to resolution, with the water and vegetation and mud and so on all manifesting in mechanical terms. But it didn't feel anything like a boardgame or a MMO. The fact that everyone was working from symmetrical power suites affected decisions, in the sense of
Can you afford to use that yet, or do you want to wait until the raft is within range? But it wasn't the focus of the action.
What brought the fiction to life, for me at least but I think also my players, was the actual situation the PCs found themselves in, and the way that situation unfolded. Being in the water sucked for the warriors because
they were heavily armoured guys trying to swim to a sandbar. The slingers were dangerous because
they were missile troops attacking exposed enemies from a position of cover. Being stuck prone in a boat you don't know how to propel sucked
because it should. Etc. The mechanics were crucial, but as means, not ends.