When you Level Up, upgrade a Bronze » Silver-tier item.

If you have 5 or fewer items, your items have +10% » +20% » +30% » +40% Crit Chance.

The first time you fall below half Health each fight, Shield equal to 20% » 30% of your Max Health.

Your Weapons have +2 » +4 » +6 Damage and Shield items have +2 » +4 » +6 Shield for each Friend you have.

When you use a Friend, your Weapons gain 3 » 6 Damage for the fight.

Your large items have +25% » +50% Crit Chance

If you have exactly one Friend, reduce its and the Core's cooldown by 5% » 10% » 15%

When you use an item, your items gain 3% » 6% Crit Chance for the fight.

Your items have 100% less Crit Chance.

The first 5 » 10 times you Burn each fight, Charge 1 Shield item 1 second(s).

The first time you fall below half Health each fight, Shield equal to 2 » 3 » 4 times the Burn on your opponent.