I think in the end it just didn't sell enough and has been abandoned by its developer. I'm not calling it abandoned because it didn't receive infinite updates — that's not a reasonable expectation — but because numerous serious bugs were acknowledged by the dev and never corrected. So now it's a ga...

It takes ages to finish AI turn in all scenarios. Pausing animations and other solutions sugested doesnt help. That could be the scenarios themselves, especially the custom designs. Try another campaign. If the issue persists, then look to the usuals: Sufficient hard drive space; disk defragmentati...