Heinrich Tillack has released a preview version of his great game DCastle, heres a description from the man himself:

This game takes the classic STAR CASTLE game from 1980 to 2004, uniting breaking puzzle games and shooters.

ARCADE MODE: You control Dr. Freak. Dr. Freak fires at Smily, who is surrounded by three oppositely rotating energy rings of twelve blocks each. When a clear line of fire is open, Smily fires back with a big “fuzzball”. Alien sparks start off on the rings, but eventually fly loose and chase you. The gameplay is intense!

PUZZLE MODE: Just intense! Just have a look at the commercial DCASTLE version