The game is a reimplementation of the old game known as Tower Toppler or Nebulus. It was available for PC, Atari, C64. The author was J.M.Phillips and was published by Hewson software.
I don't have an original, but this seems fun enough for me.
Schwertz 12/01/2013 15:59 UTC v1.1.3.1
This is unfortunately an example of not good enough reimplementation. Not a problem of the port though, PC version behaves the same way. For OP users it's better to play CPC, Spectrum, Commodore or Amiga edition of the original game on the corresponding emulator. I'd recommend CPC.
Esn 05/04/2011 23:41 UTC v1.1.3.1
It looks nice enough, but it doesn't have exactly the same timing as the original game. This is clear from the very first 20 seconds, when you can't get to the second elevator without being hit.
08/06/2013 22:24 UTC
v1.1.3.1
12/01/2013 15:59 UTC
v1.1.3.1
05/04/2011 23:41 UTC
v1.1.3.1