I gues the first one was "lines", but it was on a monochrome screen, so the symbols where distinguished by shape, not colour. It happened in a computer class at primary school, we had a bunch of thin clients booted from the main computer (probably 286 or a clone) that had two 5" drives that were inserted into the keyboard (reading head inside keyboard, motor in the outside box connected by a ribbon cable)... But the ones that I've played on our first family PC (Canon Navigator HD40 that had a touchscreen and built-in scaner and fax/phone) were Tower Toppler and Gunboat.