I've 1CC'd on Novice mode at just over a billion. Working through Original mode trying to preserve the chain at the moment. Tapping for wide spread really helps on keeping the chain when I'm boxed in a tight quarter in Stage 3 though.
459 Euro is actually closer to about 380 GBP right now, and since you're also in the EU you can deduct the VAT. It should be nowhere near 500 GBP. All 3 modes play differently due to scoring mechanics as well as armaments. But whether it's worth the money depends on your preferences in shmups.