Wondering if anyone can help me shed some light on this vague memory I have as a kid. My older brother had a friend who got us tons of pirated games for our Commodore 64/128. I'm trying to recall one game in particular - here's what I can remember:

* You flew some sort of hovercraft/tank/ship (definitely futuristic, not present-day) across a flat field towards a dark rectangular tower on the horizon.
* I'm pretty sure it was presented in a third-person point of view, directly behind the ship, with the flat horizon in the middle of the screen
* As you approached the tower, it would slowly get larger and larger - not sure what happened when you reached it
* I think maybe the sky would change shades as it got 'later' or you got closer to the tower.
* I think you could only 'strafe' left and right, and maybe slightly forward and backward - i.e. you were always heading towards the 'horizon' and the tower
* There were definitely some sort of powerups you could fly over, that would maybe give you shields, fuel, or ammo? They were represented as sort of 'discs' that kind of looked like whirlpools
* I believe the field you flew across was green - may have had obstacles or something to avoid
* I assume you shot incoming enemies with lasers or something, but I don't really remember

The one thing that stands out is how the tower got larger as you approached the horizon. It sticks in my mind because it was very similar to when I rode my bicycle across Kansas - long flat horizon with the next town's grain silo in the distance, that would grow as you approached it!

I've scoured the internet for all the search terms I can think of, and have come up empty. Anybody have some guesses?