Please i'm at the helicopter evak point but no aliens no marines all i see is invincible shooting...i also hear all the time "go" from the marines!!
This bug is huge because it stops the game right there with no chance to proceed...i tried everything but i'm stuck...this is a huge bug in the game mechanics and have to be fixed from the developers...

I also heard many tips like after the tail from the chopper go up the ledge etc...i cant because it is too high etc

Please Crytek or EA fix that this game ends for me right now after Mission 10:-(

I got same problem once when Ceph gunship not show up.
So, I restart the whole level and everything should be fine.

i did restart the whole level no change

Can't progress past Semper Fi or die also.

Steam Version and not a big fan of posting on forums but I felt this time it was necessary.
First time I got the "Move up go" with invisible aliens and no marines, just shooting guns. Helicopter was not destroyed (burning) and I could walk through it.
Verified my game cache in Steam and steam defrag.
When I loaded up the game afterwards it re-ran directx and verified my product code (that EA white box that pops up). Said ****....... did I loose everything..... but
In game account settings there and resume misssion was also there.
Resumed.
Got to point where I'm working my way towards the extraction point with the marines. Previously, with the sound glitch, it seems the drop ship dropped everything... but now I am able to progress to the extraction point with the marines. Thought "yes!, its fixed"...... killed 3 waves of aliens that drop from the ship, with the final alien being that big heavy gunners one.
Then nothing. No ship to shoot. Just didn't show up. But the "Move up Go" had stopped and there are 3 marines just hanging out. So once again I am stuck and can not proceed.
Watched video of where Im suppose to go because the whole "jump on a ledge" is not descriptive enough (maybe someone could post a pic). I know that to the left of the chopper the ledge is suppose to drop down enough to progress but it doesn't due to the scripting bug.
So I went to the left corner (thats left directly of the choper, up as high as you can be. Look at chopper, look left of the destroyed car keep looking left till you see the wall that prevents you from moving forward and in that corner) and jumped and yes, you can get up there (its not a ledge grab, just a jump). But there is an invisible barrier preventing me from progressing down the destroyed road. (shoot at the air and you'll see bullet marks. So I checked the whole area of where Im suppose to go and it appears the barrier extends at least half way and in game is just too high to jump over.

So I am still stuck and have wasted hours here. Here is what I have tried.
1) restarted semper fi from beginning. End result is always the same after I did the cache check. I see marines, there is no "move up go" anymore.... but no ship to shoot down.
2) started mission before semper fi... same result.
3) tried stacking cars and a dumpter by kicking them up to ledge (huge waste of time here). Still didn't work.
4) tried doing nothin.... let the marines do everything. While they shoot the aliens I try to shoot ship. It takes no damage and didn't work.
5) watched a video on some guy leaving the level (its near boat) but he had to cheating cuz he jumped much higher than I can.
6) tried upgrading my suite options (then found out when I restart the game I lost all of my suite points.)
7) looked for a noclip option. If its there I can't find it.

At this point I gave up.... totally frustrated. Will have to wait for a patch it seems.
In addtion my loyalty to Crytek has dropped significantly. How could you realease a game that is unplayable. How could you entice us with a, up to the semper fi point, a really fun game that works 3d great, only to leave your fans stuck and can not progress.

Crytek, you totally dropped the ball. You have hurt your reputation and fan base loyalty.

If anyone knows of "real solutions" please help.

Not sure what happened.
I uninstalled the demo. I had to do from control panel as I couldn't see it in the steam games list. When I selected to uninstall steam came up asking to delete local files. I said yes.
Started game but when I did I briefly saw a msg from steam saying it updated Crysis 2
Picked last mission before start of Semper Fi.
Played Semper Fi and I rushed it, bypassing most enemies to get to vehicle to get to end of semper fi.
With marines working my way towards chopper the following happened:
Only 1 wave appeared. The wave where you defend at the bus.
After that wave I moved to chopper and this time the barrier was not there. The road has collapsed and the blue octogon was moved to the collapsed road.
I didn't fight 3 waves. I didn't shoot down alien ship. I was able to progress to tunnel.

No idea what fixed it. Maybe I got lucky. Not sure.

same bug spotted, restarted level or load various checkpoints up to 10 times - nothing. only invisible guns shooting and nothing.
i suspect something wrong with level or area triggers - tactical advantages do not appear in visor although at the area entrance i've seen a message about tactical anolysis required. you can though pickup these shooting guns, but nothing happens - shooting remains the same, now without any guns

also found funny little trigger bug there - there is subway car with explosive barrel in it. if you shoot the barrel, part of the car falls down to the ground. i managed to drop that barrel outside the car by near grenade explosion, and when i blow this specific barrel on the ground - car broke in two and that second car-part falls .

i'm playing retail russian version of the game with latest patch available to autopatching subsystem

Got the same bug.
EU Retail version

I had the invisible marines and aliens bug up at the ship but the airship up there was visible so I managed to shoot it down. I had invisible marines shouting around me while I progressed down to where I am supposed to help the marines defend against the alien onslaught while waiting for the chopper to show up. When I were almost at the point where the second alien airship drops the first group of attackers, the shouting stopped and things were acting normally.

The strange thing is I heard a report about the chopper had been shot down (a voice says someting about *code name here* has been shot down or something like that) before the final defensive battle started.

Move UP Go was the worst part of the whole game. It never stopped till I crossed the water on the far side.. I also thought I couldn't proceed with the game but it turned out you can just sneak through ANY level of the game without really engaging anything serious, which shows just how linear the campaign is.

Long story short, I ended up taking the "boat" route up on the upper right side, dropped down to the lower deck and walked right past the "invisible ones" and crossed the water in cloak mode to continue with the game normally. Very disappointing as that buggy spot of the sp mission was the only part with the swarm gun and I had no one to aim at! in fact, I lost the swarm gun once I reached the water. GRRRRRRRRRRRR!

How did you get up there on top of the boat? Did you do it without cheating?

Reason I ask is I'm playing through it a second time and if semper fi freaks out again I'd like to take he boat path as it seems the shortest way to solve the problem.

PC Version right?

Got the bug again when arriving at the map where one have to blow up the parking house. I start to believe the bug is caused by the game expecting one to stop when conversations start, if you move past a specific spot a trigger is activated and the soldies making the conversation is moving on but the conversation is fixed to that specific part of the map, not the soldiers. Somehow this makes the game go out of sync so it can not allways proceed correctly.

There are 3 more swarm guns behind the barricades/containers on the other side of the water where one have to defend against the aliens for some minutes.

@Yosemite_SLAM
You can get up on the boat from the end pointing to where you arrive on that map.

Just played through Semper Fi or Die again on hardcoe mode.
Playing through the sp game a second time.
Was worried at first but this time it played exactly as it should.
Not saying this will fix it but it can't hurt.

Steam version.
Verify cache and defrag from within steam.
Uninstall the demo if installed in steam. Uninstall via control panel as you don't see it in your steam games list.
Load last checkpoint before semper fi mission starts.
Cross your fingers.

PC steam version. I've been through this map several times, one time no errors, another time, fell into a crack in the road near the speed camera and the game did a checkpoint save while stuck in the crack. so reloads put me back in the unescapeable crack. Chino completely disappeared from map, this caused a crash to desktop with no error. No mini boss fight in valley beyond huge hole, and chino already at the top of the slope that drops down after the mini-boss fight. Also that irratating constant nag from chino to shift it when the roads blocked by aliens when the map goes buggy. For a so called sand box game this map is tight and linear.

Also fell out of the "lab rat" map, after picking up the car keys, power jumped over the wall to the side of the lab and fell through the ground, in to the water that goes all under the map, then got stuck under the lab building with no escape route.