Ark Area is a mid-school era omni shooter with its own unique control feel. It's not the prettiest or the most complex game, but the simple way you change direction (and how it plays out) makes the game enticingly playable.
You move with the joystick and have two buttons. One to shoot and one to change your ship's direction. What this means is that if you just move the joystick and fire, you stay facing the same direction - but if you hold down the 2nd button and move the joystick, your ship actually points in the direction you are pushing the joystick. (The KLOV entry for this game has it wrong - it says there is only one button in use).
It's a little hard to explain. There are certainly other omni shooter games in which you can lock the direction you are shooting or have it follow your twists and turns, but they don't feel and play exactly like Ark Area.
There are bosses that take a while to kill and each stage looks markedly different than the previous one.
That brings me to the other important point... The game is incredibly difficult. If you don't use the 2nd button much and just shoot in the same direction (like a vert or horz or diagonal!!!! shooter), the enemy comes from all directions making it difficult for you. On the other hand, if you use the 2nd button a lot and even hold it down, you are constantly changing directions and risk flying into the baddies that are nearby. I played many times and didn't get past the 3rd stage on the default settings (there are more than 20 stages).
In fact, it's so hard that I'm inducting it into the GOTD Hall of Fame for Rage Inducing Games.
Like many games, it's better than it looks or seems at first sight, so stick with it and try to live longer than I did.