After each round, you can select one piece of equipment to take from a list of three randomly-selected potential rewards. Due to the randomness, you may find yourself improvising around an unusual selection of gear. Generally the most important pieces of gear to upgrade regularly are your swords. If you can't get or don't need a sword upgrade, you should select a piece of armor, or try to upgrade what's in one of your less-important slots (boots, trousers, gauntlets, and trophy). Between rounds, you can check with the vendor to purchase potions, oils, and other enhancements for use in the next round. It's a good idea to keep armor fully-slotted with cheap enhancements, though slotting your swords with runes is going to be prohibitively expensive early on. Potions and oils in Arena mode work the same way they do in the main game. They last until the real-time timers for them run out. Skills that affect potion and oil duration work the same way in this mode that they do in the main game, too.
Experience does not work the same way in Arena mode. In Arena mode, Geralt gains one character level at the end of each round. If you want, think of each round of combat you clear as being worth 1,000 XP.
The arena holds some circles that you can take advantage of if you like. Downstairs, you can find a circle of power. Near the boxes you use to arm-wrestle, in a corner next to a rack of barrels, is a circle of strength. The circles do not reset until you’ve survived round 30 of combat and the waves begin to repeat, so think carefully about when you want to use them.
There is no increase in difficulty when the fights begin repeating after level 30. You receive the exact same oren rewards, although your item rewards will naturally vary. Your rewards at this point are primarily enhancements and mutagens, and occasionally armor. Weapon rewards are relatively rare.
Just as in the main game, level 35 is the game’s level cap. Geralt cannot level up any farther. Once you’ve gotten a Geralt to level 35 in Arena mode, you’ve effectively beaten it. You can have fun starting over from the beginning and trying to level Geralt up differently, though.
Sometime near round 30, you might have the opportunity to take the Operator’s staff. This weapon’s high freezing and incineration values make fighting human opponents completely hilarious. Seriously, it’s loads of fun and we highly recommend trying it out.