Can't deny that it rocks. A bit simplistic, esp. the wowowo-chorus.
Concerning writing credits on the new album; the lion's share of the songs (9/13) are composed by the band themselves with Miku providing lyrics for 10 songs and Saiki being a co-writer on 3 of them. A remarkable turnaround from being a poppy 'cover band' into a self-produced hardrock force in such a small time I'd say.