Denarius

The Rignalian race have decided that they want to colonise the planets of the
Solar Sytem and their moons. To help support their life-forms they need pools
of chlorine to survive and so in their space arks they have placed the pools
in various cities. You have been tasked to fly your space fighter over 16
infected cities blasting the alien crafts and collecting as much of the
chlorine as possible to save the Solar System.

The game is a top view vertical shooter with the screen scrolling constantly
upwards as you blast and collect. As well as the enemy crafts to blast or
avoid you also need to avoid obstacles or you lose one of three lives. As well
as your laser you can activate one shield for a limited time for each city. On
the surface of the city, the chlorine pools are small squares in clusters and
you need to fly over these to collect them. The number you collect is turned
into points at the end of the level

When you survive a city you then move onto a bonus level which sees walls of
gas move down the screen towards you. There is a gap that needs to be flown
through for each wall or if you touch the wall then the bonus level is over
and it’s onto the next city. A joystick is used to control your space fighter.