Risk System doesn't seem to have gained much attention, a shame really since as far as shoot 'em ups go it's fantastic and at least tries to be a little different. A shooter where instead of dodging enemy bullets, you need to get up close and personal to charge your ship up. Honestly, it's good.
At release, the Linux version did suffer from one major issue. Due to a bug in GameMaker, unless you used an external tool to cap the FPS, everything was too fast. They've now solved this, with an update released this week.
On top of that, they've also added in an endless mode once you finish the main game, the ability to skip cut-scenes was added, a bunch of new leader-boards were added in for you high-score chasers and the boss difficulty was adjusted.