I'm not sure if this is all instrumental. I could imagine Nuno and Zakk singing some of their songs and Nuno doesn't have to sing Extreme stuff, he's got a lot of other material (Nuno, Mourning Widows, Population 1, Drama Gods) where he was the lead singer. Although those tunes are probably not that well known outside his fanbase.
And no, Midnight Express wasn't the best track on punchline, in fact I thought that, apart from the "chorus", it was one of the weaker instrumental tracks around.