Doujin publisher Nyu Media have released PC shoot-em-ups Kamui and ALLTYNEX Second on Steam. Along with Reflex, which was released earlier in the year, the games form the Tale of the AlLTYNEX trilogy.
Kamui and ALLTYNEX Second have been updated for Steam with achievements, online leaderboards, and cloud saving. The soundtracks for all three games are also available for purchase.
Buying the standalone games and OSTs will cost you $7.99 per each one, but you can buy game + OST packs at reduced prices.