Neoclyps

Neoclyps is a game very similar to the game Defender in concept.

It's a side scrolling space shoot 'em up has you flying a spaceship over alien landscape. You can move up, down, right and left, and you can shoot.

The game is quite well designed progressing from the beginner levels (1-4) through to the Ace levels 13 and above. To progress through the levels you must destroy key targets, radar bases, in the city below without crashing into any of the other buildings. The targets are cunningly placed and become more difficult to access. Fortunately, every time you down an enemy space ship you get a temporary shield that helps negotiate the city scape.

Naturally the first four beginner levels are fairly easy, but as you get to the intermediate and expert levels the challenges increase and the difficulty level ramps up.