Guys tips for the endless mode get rid of awkward items dont worry about running out of stars i got rid of chest armor axes and helmets the flat items arent much of a bother ex katana and club and for the people saying that it doesnt register as an achievement make sure you have 180+ seconds and submit your score my achievement didnt register until i submitted my score so try doing that. Good luck guys happy achievement hunting
You cant upgrade weapons, but i think you mean the weapon slots? After the collection round youll reach the "eauip your hero" screen, ubder your hero you can see "Spend your gold here", while collecting you may found some godl which you can invest here, eighter for "buy more equip slots" (the more equipment --> the better your heros chances to win) and "buy more grid space" (this enlarge the place where you store the equipment).