Board Thread:Questions and Answers/@comment-38784665-20190312015051/@comment-38784665-20190312181913

Anon421 wrote: Ideally, you should complete all the remaining Tournaments, Challenges, and Survival (two times, with and without Eclipse) first. Save the boss for last. You don't even need to fully/max upgrade all your equipment, it's possible to defeat them even with half-upgraded items. Max-upgraded items only make the fights much easier.

Completing all the leftovers will grants you with all the possible coins you could have, therefore allowing to upgrade your items. OHHH thanks a lot