Lode Runner

The player controls a stick figure who must collect all the gold in a level while avoiding the guards. After collecting all the gold, the player must reach the top of the screen to advance to the next level. There are 150 levels in total, which progressively challenge players' problem-solving abilities or reaction times. Levels have a multi-story, brick platform motif, with ladders and suspended hand-to-hand bars that offer multiple ways to travel. Guards can pick up gold bars by running over them, but any individual guard cannot carry more than one bar at a time. The player can dig holes into floors to temporarily trap guards and may safely walk over them. If a guard is carrying a bar of gold when he falls into a hole, he will drop it and the player can then pick it up. Holes dug by the player fill in after a short delay. A trapped guard who cannot escape a hole before it fills is consumed and immediately respawns in a random location at the top of the level. Unlike guards, the player's character may not climb out of a hole, and will be killed if it fills before he can escape. Floors may contain trapdoors, through which the player and guards will fall, and bedrock, through which the player cannot dig. The player can dig a hole only on adjacent sides and may not dig directly beneath. In order to dig through multiple layers of bricks, the player must create a gap whose width is at least equal to the number of layers. However, exceptions to this rule arise when the player digs from the position of standing on a ladder, or hanging from a hand-to-hand bar, which makes it possible to repeatedly dig and descend one row. This kind of digging is involved in solving many of the levels. The player starts with five lives; each level completion awards an extra life. If a guard catches the player, one life is subtracted, and the current level restarts. The player's character can fall from arbitrary heights without any injury, but cannot jump. The player can also trap themselves in pits from which the only escape is to abort the level, costing a life. Enemy AI The guards do not always take the shortest path to the player and can move in counterintuitive ways. For example, when the player and a guard are on the same ladder, the guard will sometimes move away. In general, depending on their exact positioning relative to Lode Runner, the guards sometimes appear to be repelled. Mastering the game involves developing the intuition to predict the movement of the guards. Permitted contact The player may come into contact with a guard directly from above, where the stick figure's feet touches the guard's head. This is what enables the player to walk over guards that are temporarily stuck in a hole which has been dug. It is also possible to make this contact while both the guard and the player are falling. This is because the player not only runs faster, but also falls faster. Moreover, it is possible to survive the feet-to-head contact while a guard is standing on a platform and begins to move. Both forms of contact are necessary to solve some levels. It is sometimes necessary to liberate a trapped guard by digging while standing on his head, but then moving rapidly in the opposite direction when the guard begins marching to freedom. In a few levels, it is necessary to use a falling guard as a bridge to reach an otherwise unreachable area. One subtlety is that if a down movement is initiated while standing on a guard's head, or briefly touching the guard's head during free fall, the consequences are fatal. Trapping and using guards In some levels, guards can be deliberately trapped in various ways. For instance, they can be lured into entering a part of the level from which there is no escape. In some situations, the player can liberate trapped guards by digging them out. In some levels, the player must exploit the guards by letting them collect gold pieces which are positioned such that whoever collects them will become trapped. When the guard collects the gold and becomes trapped, the player can release the guard and then later steal the gold after it has been dropped. In some levels, there are gold pieces that can only be collected by digging holes to trap and kill the guards. Deceased guards come back to life from locations near the top of the screen, which may allow them to reach parts of the level that cannot be reached by the player. Traversal orders Some levels require careful ordering of traversal, because they are divided into zones connected by passages which are impossible to navigate in the reverse direction. If a gold piece remains in an unreachable zone, the player may have to abort the level, unless there is a way to coax a guard into bringing the gold. Timing Some puzzles in the advanced levels are time-sensitive. The player must dig in order to penetrate the interior of some cavern to collect gold, and quickly return the same way before the digging repairs itself. Other puzzles require deliberate timing among the digging actions because the player must run over previously dug-out tiles that have just repaired themselves, while having enough time to pass through ones which have not yet repaired. ==Development==