amok: there are also only seven story archetypes in the world, so there is no point writing any more...
This statement is like saying "if they can put a man on the moon, why can't I buy a hover car?" One has almost nothing to do with the other. The narrative for a game, especially the typical platform shooter, is rarely longer than a few paragraphs, the average novel is somewhere between 80,000 and 120,000 words and is the entire creation of the authors imagination unhampered by the limitations of a computer.
amok: What game (made in Gamemaker) is better though? I can't remember any other game on the hoof right now.
Just take a look for platform shooters, you'll find quite a few, many of them are spectacular, though few have the scope of Cortex. Then again, all scope is in video games is development time. I will acknowledge that it's hard to build a 2D platform shooter and make it truly unique because it's a 2D platform shooter. Even the inclusion of multi-player and defense structures don't really make the whole thing riveting.
NOW.... if I had my way, I would 1) have the game redesigned with the models from the trailer, they actually had character and 2) I would give the game the functions of a 2D platformer, but make the levels be be rotatable 3 dimensional spaces ("solid" platforms on a rotatable, invisible cylinder controlled by the player). That's what I thought when I played it and I still think it would make both the offensive and defensive aspects more exciting and strategically more dynamic.
EDIT: edit for spelling and grammar... yep, still terrible.