I when into a tunnel,the current inside was very strong and before long I was travelling at a high speed,I ended up in a huge room after a 1minute plus ride.
Without any warning the whole place become pitch black and when the lights came on,I see aliens swimming about.There was about 8 of them.Lucky I had my cloaking system on so they can't see me.
I killed them no sweat at all and the whole place starts to shake.Above my head there was a huge current and I entered it.I finished that level.
I was so relieved to see daylight but the whole island became an ice land.Its snowing and aliens starts to pour out from the ship.I rendevous with my squad mates and I completed the level.
I then completed another 2 levels during the next hour and the last level arrived.
The final boss was a huge ship and luckily I got my TAC cannon which fires mini nuke grenades.After i destroyed it,my character said 'its not over'.The game then ended and I am waiting for the expansion pack Crysis Warhead.