Black Pixel Land

One of my personal favourites. Here, look at featurelist:
~ 42 levels from easy to difficult for long-enduring fun
~ Integrated level and campaign editor
~ More than 60 different object types, including lasers, teleporters and even electronics parts
~ Three playable characters who need to work in teams for some levels to be solved
~ Deluxe graphics and sound effects
~ All game graphics can be customized
~ Available languages: English, German
~ Some levels are too hard and nearly impossible to beat !

Official web + download
[UPDATE]: Mirror on Mediafire