Intense stylish shooter.
Your best bet to enjoy is is connecting a controller into an USB port, it might be an Xbox 360 controller or not, I particularly love that controller, and use the dual stick to control where you go and where you shoot. There's not much else to it really. There's a slow motion system that at a mere press of a button is triggered, easier to kill, easier to avoid being hit at difficult situations; it's also worth more points because, frankly, the developers think it's cooler, and it really is.
Sometimes this kind of game is all about what the player makes out of it. It's fun to just fool around trying to survive as much as you can without firing a single bullet, it's nice to play for high-scores, sometimes it's nice just to shoot things and watch them explode. A key feature on this game would be combos, if you destroy at least 5 enemies each second your combo will keep on rising, after 10 you get a bomb, if you detonate this bomb anything within radius will go boom, after using this bomb if you manage to keep killing 10 enemies more bombs will pop up for you. Result: Many baddies will go boom. Which is good.
Raise combos for sick scores and higher levels, at each level up a power up appears somewhere in the circle, if you manage to walk over it you get a permanent boost on combos. After 10 levels you get a new life. Simple and effective. Expect to have more, stronger, faster enemies and you advance. A controller is not required, though it's preferable over the WASD limited range, even though shooting with the mouse is pretty okay and in certain situations better than the analog stick.
If it's a simple game the best thing the developers could have done to improve it's replayability would be making diverse game modes. They tried, but not hard enough. You do have some interesting modifications like a more where you can't shoot and has to search the circle for a red bomb to explode and free you from such reckless amount of dangerous situations, you have 5 seconds until the time runs out to find and acquire the bomb, as soon as you get it, you must search for the other one. It's a very intense game mode.
Other variations can be found though nothing fancy or extraordinary. Even the challenge mode which generally saves many simple games failed a little bit in my opinion. It's actually a pretty neat idea, but poorly executed. You have 20 challenges and you have to go through all of them in a row. If you had them separately or in fewer sets like 5 of them would be much nicer.
The graphics are absolutely beautiful in their own way. The soundtrack is pretty great also, though not much variety will be found. It's also interesting that the two main themes are so different from one another, one of them is a very upbeat techno while the other is a monotonous ambient track. It's hard to have choice but it's ironic that they're so different from each other
There's not much else to be said really, it's a very simple game but can be pretty challenging and addictive, you just need to keep an open mind over it and not expect something grand. It's a nice title to play from time to time, set personal goals, beat highscores, and just have some fun.