Megashark + crystal bullets.
Make a long platform. Keep running in one direction, and dodge spazmatazim's fireballs. Unicorn mount is good for this.
Go for spazamatasm first.
In the 2nd phase you will need to manuever around the charges, but against the flame breath you can just continue to keep running in a straight line.
Once spaz is down you just need to take out retinizer by itself, if you keep moving most of the shots should miss.
Band of regen doesn't do a whole lot if you want a defensive accesory use a philosopher's stone or cross necklace, or one of their upgrades.
Power glove won't help against the twins, they're immune to knockbakck and the speed boost only really works on swords.