If you like odd tower defense games and have five dollars, get it!
In the Dsi's best attempt at a story you're a newbe space pilot coming up in the ranks as you go through waves of hostiles through thirty different stages with you trusty robot. Each stage is set up with different ships in a fleet ( Or sometimes you just have your ship ) and you try to take out all the enemies by attaching weapons to designated areas on your ships. There are a total of eight weapon and they do have a lot of variety ( i.e. Some hit invisible enemies, some do damage over areas, some have wider range of fires, and some you can attach to the inside of you're ships ) and some of the better weapons require that you invest crystals into them each mission to research them so they can become buyable. After you kill an enemy they drop orange orbs that you use a currency. You simply drag the stylus over them to collect them. After each wave you earn a bonus for how many unspent orange orbs you have and crystal that you can put into researching a weapon, increasing the bonus of orange orbs you get after each wave. You can also invest orange orbs into getting one crystal but the price increases every time you do it. You can also invest crystals into SoS cards. You get SoS cards after each mission and every time you replay a mission and they can really help you out in a pinch ( Like give extra orbs, better range, free weapon, help from a bounty hunter, super bomb and more. ). You get a perfect if you don't let any enemies away and get a better perfect if you don't use a SoS card, so they're is a lot calling you back to replay missions.
I'm personally really enjoying this game and if you like good Tower defense game and have a Dsi, I think you will, too.