ijuin

We're all gonna DIEEEEEEEEEEE!!!!!!

Having a nuclear engine is a neat idea, but rather than making it both higher-thrust and higher-fuel-efficiency than the standard liquid engine, I would rather it be lower-thrust and higher-efficiency (e.g. half the thrust but four times the efficiency), reflecting how nuclear-thermal rockets work in our world. That would mean that you would need boosters to lift off, but you would gain the high fuel efficiency for your core stage.

Did you check to be certain that the combined thrust of the firing first stage engines exceeds the combined weight of the entire vehicle? It's not going to lift off if it can't lift its own weight from the pad!