Im nearing the end of COD:WaW and this has to be the first "on rails" shooter I've played in atleast 4 years. 

The whole game is in trenches, or in building coridors or in tight streets of Berlin and there is always 1 way to go, 1 way to deal with the an enemy. It reminds me of Killzone 1 actually...

For example...there are 3 German tanks blocking the path. Everything stops and the teamates wait until you get a bazooka to clear the roads. You must get a bazooka...or the game doesn't move forward. This is just bad level design.

I thought Halo 1 changed the FPS genre where you could deal with any obsticle or enemy in multiple ways hence getting replay value.

In any case, has anyone replayed the SP campaign for this game. What kept you going the second time around? It looks like this game will be on the trading block for me in a few days once I take Berlin down...

Well I played it once with the regual settings. I played it again on the hardest mode and gave up after 4 missions I think... very boring, it's just a "grenades party"!

The last FPS single player i found to have any replay value in singleplayer at all was Perfect Dark... and even then it was only to go on a killing rampage vs everyone on the stages that were supposed to be all stealth.

It's not that bad. The best Treyarch game until now and I will definitely make my 2nd playthrough on veteran after I finally beat CoD2 and CoD4 on veteran (only 2 missions in each game left).

But it has a co-op mode, so I will play it with several friends before I finally give it up

I think Farcry2, Crysis and Halo 3 are currently the leaders in SP replay. All 3 have multiple ways you can approach an enemy or goal and all 3 don't have stupid limitations like...

"Snipe this general or its game over" or "protect the vehicle or its game over"...If the vehicle is about to blow up, you should be able to leave it and find another means of killing the enemy.

Halo 3 gets extra points for 4 player coop which results in rediculous amounts of carnige on legendary difficulty...

I think Far Cry 2 has no replay value at all. The missions are waaay too similar.

On my own. no i dont wanna play again.
With friends on co-op its bearable... as long as were not playing it on Veteran. I HATE veteran for the grenade fest that it is. other than that... the game is bearable but not as good as Cod 4 imo. Modern Warfare 2 will be THE fps of the decade

lol. I know...go kill this, go blow this up... I found it varied enough to keep playing tho for some reason. Its a much bigger game tho...so you're technically replayig it as you're playing it :) 

If it wasn't for the Zombie mode, I wouldn't have finished the single player campaign. I thought this was the worst campaign of any FPS I've ever played.

I grew tired of "on rails" a while ago.  I played COD4 on the PC mainly because I was supprised that it ran at all on my old PC and looked good. I HATED THE WHOLE EXPERIENCE and vowed to never play a game like it again.

You mention the 3 tanks and bazooka situation.  THE WHOLE F***ING GAME IS LIKE THAT!!  On the easy setting of the game you can just run to certain points and the game automatically moves forward.  Typically you will only have to do one thing and the game will move foward.  Its so obviosly scripted to work like that the experience quickly becomes tedious and boring!

Later I was persuaded to get COD 4 for the 360 and try the multiplayer as it is supposed to be the nuts.  Its better thatn the SP aspect of the game but its not for me.  Its too old school and not in a good way!  Matches are all set in what feels death arenas and not a modern warfare front.

Anyway back to SP.  co-op campaign for WAW looks good but nothing to make me want shell out the dough.

My favourite SP FPS experience has to be Goldeneye/Perfect Dark where you have to complete SP objectives and campaigns to unlock further MP and SP elements/components.  For example complete a level on one difficulty to open up the next difficulty level.  This next difficulty level has the normal changes like better AI, less health/ammo but also extra objectives that much be completed!  Why arent more games like this?