Map : IX
Weapon : Shotgun at top of Danu & ICR
Staff : Sceptre Of Ra
Perks : Danu, Speed Cola, Secret Sauce, Timeslip (In Odin Slot)

Strategy here is to simply not get hit, you spend the first couple of waves in the Colosseum and you shouldn't be losing your multiplier.
Normally takes you towards Danu, go upstairs, get the shotgun which is awesome when pack-a-punched, and simply train upstairs, without going down.
It will then proceed to take you to different areas.

If the area is a Tower, head to the top and train up there.

When in the pit grab the shield, if you have the tortoise perk then its pretty powerful, but if not when you get hit in the bum you will not lose multiplier due to the shield.

The only real area of concern here is the Podium.
Very small, very awkward area. Lucky when I got here I had 248,920 and it was pretty much done.
Strategy for that area is to simply hope to god you have Danu (it will send you into berserk for 9 seconds rather than downing you).
Make use of any power ups that are dropped (hopefully an insta kill)
And finally use the Spectre Of Ra, that thing when level 3 is an absolute beast.

Worth 15 Gamerscore.