This is a fun game, and just like Kiroko commented below, the gameplay is addicting. It's fun to make or simply discover OP pairings. I really like how later stages make enemies immune to certain attacks and then changes their resistances mid-fight, it spices things up and encourages you to make new pairings.
I tried the latest version and just left my score in the leaderboard! Incidentally I discovered that Aya x Eiki (machine gun!) and Mokou x Youmu (sword machine gun!) are really good in the right situations, haha.