Spectrobes, with less, but more
While exploring you'll find minerals and fossils, both to be used face to face with spectrobes in the incubator, face to face as in for probably the first time you can literally go into the incubator to train and feed spectrobes.
Battling is a great way to level up your spectrobes and Rallen/Jeena. The battle system allows a player to say whether a spectrobe attacks or retreats, and Rallen & Jenna are much more effective than they were in the first game, with people collecting "legendary weapons" for a very fun search on all the planets, all over the planets, I myself haven't even found them all!