This is the first of the five games on Blue Ribbon's Games Disk Number Two, price £9.95, although the games are also available separately on cassette at £2.50 each.
Screwball is strongly reminiscent of Blue Ribbon's Q-Man, based on the principle of jumping about from square to square changing the colour of the square as you go.
You have 60 seconds to change all the squares in the 3D grid, after which you move on to a new grid, which is rendered slightly more complicated by having gaps in the middle of it.
Unlike Q-Man, you can't kill yourself by hopping off the edge of the grid. In the place of hostile bouncing balls are aggressive snakes. There are villainous black bugs out to get you. They don't even play fair - don't count on them moving around simply by walking on squares like you!
You can fight back by digging holes for them to fall through. And if you're in a really tight spot, you can hyperspace to the top of the grid - but you might not survive the experience.
And that's all there is to it - simple, but reasonably entertaining.