kazama bee has made several TD games, all with good graphics, all with the same flaws. Dude: you need a working next wave button, hotkeys, and multi-tower placement. That's all that you need to add to make your games wonderful.
Win: Surround your blockhouse/castle with puckle cannons, outside that put a ring of infantry, outside that put a ring of barricades. That'll give the cannon and infantry time to finish off engineers.
As soon as a plane enters, get it down to 4000 feet. Set them up in a circular orbit. When a plane is in a place where it can turn into the localizer triangle, Set it to 3000 feet, 200 knots... and hit APPROACH, NOT ENTER. It will descend and turn and slow (or speed up) at the same time.
madre de Dios, it's a tower defense game. with not-wonderful graphics (well, they're wonderful, but not *intense*. like cpu-intense!). So what's with the CPU-hogginess?