If you are through with all the 75 levels of Episode I take the next challenge. This second episode of Lode Runner series by ZX Games features a different and much tougher set of 75 levels, which were designed by Douglas Smith and unknown kids in the distant 1983.
The levels get progressively more difficult and are advantageous only to the angry Bungelings controlled by the AI that are mean as ever. You are all alone to struggle against the 1983 AI brains, beat it to the end. Maybe relive the levels you have already completed or even tailor them to your taste by using the in-built level editor.
There is also the quick save & load feature to rest your weary fingers upon and prevent you from the collapse should the game get too zesty. Finite lives are an atavism, so there aren't any.
Smooth control engine is a no-annoy factor. Full-screen and window modes add up to the convenience.