I'd say it's a job well done! Grid systems can be tough sometimes, and the fact that you even have enemies navigating the grid to follow you is very impressive. Needless to say you're off to a good start.
Once you get comfortable with the programming concepts I'd highly recommend you hop to something like GameMaker or Unity so you can keep furthering your skills beyond GameLab.
Your games reminds me a lot of my first games too, and make sure you don't get stuck on Drag and Drop coding for as long as I did