A well made and suprisingly addictive game.

The best advice I could give any game developer is to always start out at a genre that is simple to work with. In the case of Game Maker enthusiast, always make a shooter first. Sol Wars, is a game that blends overhead shooting with turret-defense in a way that is both simple and intuitive.
The game has the player flay in space protecting a massive space station from an endlessly spawning horde of enemy ships. As time passes, the enemies grow stronger, forcing the player to either upgrade his ship or create a satellite turret. The player can also add turrets to all of the planets of the solar system, adding some much needed strategy to the mix.
The only major gripe I had with the game explosion graphics. It may seem unfair to compare this game to Sins of a Solar Empire, but particle effects made with Game Maker are the norm these days. Here, there is simply no excuse.