Tetris-inspired blockbuster TiQal is this week's Xbox Live Arcade release, so don't bother trawling Marketplace for Ikaruga - because it's not there.
Microsoft recently released the list of the next few Arcade releases, which includes Capcom's Commando 3, Rocky and Bullwinkle and lots of board games. At least Commando looks decent.
The Mayan themed puzzler has you dropping and spinning different blocks, which the aim of matching colours and destroying enemy walls. Like Tetris, then.
It costs 800 Microsoft points (about £6) and includes 120 levels, as well as a co-operative mode and Xbox Live head-to-head play. Head over to Xbox.com for screenshots.