"Surprise" Ending (Spoilers!!!)

Rating: Null/10 (6 September 2004)

So many plot holes. Where to start?
I knew that the predator that escaped with Alex had an alien embryo inside of him because he was attacked in the pyramid without his helmet on. But why would a warrior take off his helmet in a place crawling with "facehuggers" and full grown aliens? Removing his helmet made him vulnerable to physical attack and deprived him of his advanced visual sensor devices. If he wanted to take off his helmet so that he could mark himself with the alien's blood, he could have done so after his trials were over. I thought that the alien inside the predator was going to burst out after they got to safety, scamper off to grow up by using the dead survey team members for food, and then come back and stalk Alex. This would have made more sense than the alien queen surviving the explosion and then digging through hundreds of feet of solid rock and ice. A final one-on-one showdown between Alex and the alien would have been a nice parallel between the original alien/Ripley conflict.
By the way, how did the alien queen dig through all that ice? In this movie we saw that the queen was kept in deep freeze. In Alien Resurrection we learned that aliens don't like extreme cold. I'm sure the predators put the pyramid under ice to prevent any aliens from escaping. You could argue that the intense heat from the bomb heated up the area long enough for the queen to escape. However, that intense heat should have also fried the queen to a crunchy crisp.
Why were the predators always being surprised by the aliens? Their visual sensors seemingly gave them the ability to see through (solid rock) walls.
The last scene on the predator ship with the predalien bursting through the dead alien didn't make sense. A highly advanced, space-traveling species like the predators would certainly have quarantined and scanned their fallen warrior for any alien embryo implantation. I know they wanted to set things up for a sequel. They could have done better by giving us a suspenseful battle on the surface and then leaving us guessing as to whether Alex had an embryo inside her.
Of course, I realize this film is intended for a younger audience than the original films, but I think they could have entertained the teenagers without insulting the intelligence of the adults.