Is there any evidence as to how eXistenZ really ended?

My understanding is that the last scene takes place in the real world. My reasoning is as follows: The story elements of each game session are drawn from the thoughts of the players. The in-game story involves a working gun made from bone that at one point, (possibly more than once, I can't remember), the dog finds and carries to Pikul and Allegra. The plot-point of the dog bringing them the gun is incorporated into the story from Pikul's and Allegra's thoughts because they know that in the real world their sheepdog is carrying guns for them hidden under a shaggy false mane.

When they shoot the game designer, the other players are unsure whether they are still in the game or not. This is consistent with the claims made by supposedly fanatical characters in the movie about the reality-deforming effects of virtual-reality games.

The final answer I really could bring in the most logical way is that in the end they were still in the Trancendenz game but above that they were in Existenz. (Trancendenz is the game they are testing simultaniously within the players and Existenz is thr god simulation, the main one, it seems they have lost their senses when they entered Trancendenz). Anyways, how they were still in Trancendenz, because the dog didn't have some simulation helmet equipped and the dog couldn't enter trancendenz without it, though the church didn't look real if so, why didn't they go outside? The main answer to this labirynth is that, the real creator of all simulations, saw that the game would finish having the players confused of what is resl or not. By all this I'm not saying this is the last answer because the movie is interpretational free. Thanks.

I think before Allegra and Ted go back to reality at the end, Allegra says that her bod was infected and that she would bring that infection back with her to reality. When that happens the dog is infected too and reality is corrupted.

Its not supposed to be open to interpretation. The movie clearly illustrates that events in the game came from the thoughts of the two assassins and at the end its the real world. It is clever but I feel like it was lost on most people, as with Inception, who follow the belief its a cop-out 'is it or isn't it' situation. Watch more carefully.