Thundercade is a vertical shooter that's a little different than the standard jet or chopper fare. You are riding a motorcycle and fighting enemies that are on foot, in vehicles, in submarines and in tanks.
Because of the theme, the physics and craziness are a little more down to earth than other vertical shooters. The game doesn't become overly flooded with enemy fire. But, because you are on land, there are obstacles to drive through, over and around since you are on a motorcycle (as opposed to being airborne). This makes moving around the screen somewhat more important than other plain vanilla vert shooters.
The controls are simple - just the typical two buttons (shoot and bomb) to go along with your joystick. What's really more fun in this game is the power-ups. They mostly come in the form of sidecars that are parked around the landscape. Pick one up and it is attached to your motorcycle. It may wind up increasing your shot forward, or adding a left or right shot to your gun. Pick up more as you go and you can wind up with additions that shoot in every direction. As there are guys on foot and tanks approaching from every side/angle, these sideways shots are important.
And yes, I said "submarines" despite the fact that you are on a motorcycle... you'll see.
Graphics are good - cute and nice little details. In fact the whole game reminds me a little of the format and look of GunSmoke (without the western theme and the great button layout that GunSmoke has).
This game was actually the first in a series of three. The last of which was Twin Eagle II (a previous GOTD to which it bears no resemblance).