There are two control sets to choose from, mouse or keyboard. The mouse allows for somewhat smoother controls, and its auto-fire may make it a good choice for newcomers. (Or those of you lacking the QWERTY keyboard.) You'll fly through vertically scrolling space taking down enemies who try to swarm the screen with firepower, and collecting the coins and diamonds they drop to spend on upgrades between levels. You can also use your Shockwave ability to help block enemy fire, among other things, which can give you a bit of breathing room as things get tougher.
The shockwave is pretty much the 'bomb' element. Every SHMUP (SHoot eM UP) provides one 'get out of jail' weapon that you can use to even the odds. The most common is a 'clear all' bomb, but Starmageddon opts for a rechargeable shockwave. This blasts at a radius around the ship, damaging enemies and absorbing bullets. It creates a tiny and brief pool of solace in the middle of a firefight (and becomes indispensable during the later boss fights). The Shockwave has its own upgrades to increase its damage, spread, recharge period and duration.
On the one hand you have to question the absurdity of sending one pilot to take out a massive hostile force. Sure, many games in the genre have attempted some vague plots here: "A lone pilot has a better chance to infiltrate the enemy forces", "It's a new prototype spacecraft and we only have one" or the always reliable "They killed my DOG and they must DIE". But on the other, these enemy armadas always end up hammered to oblivion by such a lone craft, partly thanks to its ever-expanding repertoire of super-weapons. One could also ponder why not just give all the weapons to the pilot from the start, but it is becoming clear that as the trigger man it is not your job to ask questions.
So, for whatever reason and whichever tactical handbook involved, you are heading into space to shoot down a colourful variety of enemy spaceships, always culminating to fighting a huge boss ship at the end (Come to think of it, why does the boss always fight alone.. you know what? I don't care).
Analysis: SHMUPs come in all shapes and sizes and many different gameplay designs have been introduced over the years. It can get as simple as the super bombers of 1942 or the colour-switching madness of Ikaruga. But at their core these games all share certain attributes to define their pedigree. First, and obvious, is the increase in weaponry. In Starmageddon you collect coins and multipliers, all in aid of buying upgrades for your weapons. Eventually you can shoot in all directions - and each weapon has three upgrade levels to unlock. You can also purchase shield upgrades and improve the ability of your shockwave.
Finally we come to the most important element: pattern recognition. A fanatic of the genre once told me that these top-down shooters are not action games, but puzzles instead. The trick is to recognize the patterns and move accordingly. Starmageddon definitely shows this off in its boss fights, though during the intermediate battles things can get a bit too hairy to really see what is going on (this is where the Shockwave helps a lot). But in holding to the pattern tradition, you do not actually shoot in the game. Instead the ship fights on its own volition, leaving the flying to you. In a way Starmageddon is ALL about pattern recognition (or, at the least, dodging those damn bullets).
A nice touch is that you can replay earlier levels, taking advantage of new upgrade to earn some extra cash and upgrade your abilities early on. Going straight from level to level is not advisable: you won't unlock all the upgrades in time and by the last two levels you will need everything your armory can offer to have a fighting chance. Starmageddon is aimed more at novice SHMUP enthusiasts: it is not terribly difficult, though it has its moments. The largest moments of panic and frustration, though, come when you lose control of the ship because your mouse has moved off-screen (you can, alternatively, use the keyboard). This niggle and its lack of complexity/challenge aside, it's a fun game to spend an hour or so on. So go on, avenge your dog.