This game is a version of Penguin. You don't blast or zap the aliens - you crush them instead!
You control a robot which is in the middle of a cold-store full of ice-blocks. Also in the cold store are spods which you must avoid at all costs. You must also destroy them, if you want to get anywhere.
So, to kill them, you crush them. This is achieved by moving your robot into a position where there is a block of ice in front of it, and a spod somewhere in front of that.
You give the ice-block a shove, and depending on how quick you are, the spod should be crushed.
You can also kill the spods by stunning them when they are beside one of the four walls, and then walking over them.
When you've done that, you are then moved on to the next 'sheet' where the whole thing starts again. Bonus points are scored if you can line up the three special blocks into a line, but I give warning, it's not easy.
Control is by keyboard or joystick, and each sheet gives a different 'maze' of ice which forms into more complicated patterns as the game progresses.
Altogether, Noc-A-Block is a good game, with clear, smooth graphics and plenty of colour, but it could be improved with more sound - worth looking at.