Goofs

Sending O'Neill back to Kelowna on a diplomatic mission doesn't make any sense, looking at every single detail of his well-established personality. However, knowing O'Neill's personality and previous behaviour, it's more likely a deliberate act by General Hammond to appear to his own chain of command to be following protocol but also expecting O'Neill to stamp his own defiance on the mission, as he has several times previously.

In some of the shots of Kelowna, smoke can be seen going down the chimneys instead of out.

During the opening sequence the name on Sgt. Harriman's uniform shows "Norman Davis".

Jonas says he arrived at SGC because he was able to figure out how to use his planet's Stargate to dial Earth. Yet without a GDO there would have been no way for him to get past the iris.

When O'Neill asks Jonas why he is here, Jonas replies that General Hammond granted him passageway - suggesting he spoke to him so the iris could be opened.

Jonas isn't affected by the radiation when he stands up and watches Daniel go through the window to remove the core. He should have been affected immediately when he stood up in front of the window.

It is implausible for the Kelownans to invite space aliens, only just arrived through a mysterious Stargate far beyond their level of technology, into their version of the Manhattan Project, especially given they are characterized as deeply nationalist.