Seika SE's new update contains 15 new waves, including 3 SE waves, and 1 X wave. It also contains a new medal and boss.
I've decided to finish making all the waves for this "Default" mode, then mayby add a few maps to it, then work on the next mode. Which could be Survival, Clan, or Vs. Mode. These are official updates that will happen soon, stay tuned!