The game is not overly difficult, but it is really good and fun to waste time with. Personally I feel like there should be some kind of upgrade system, and levels. After every 10 shots you get to visit a shop for upgrades (spend your points on things like seeker bullets, shield busting bullets, ect), then the next level adds something new that the last level didn't have (shields on the enemy ships, enemy ships have a way to divert my bullets, ect).