As it says on the box, this is a LEGO themed Keen mod released by Ilsoap in 2003. In fact, after 12 years it still stands alone as The LEGO Mod. The graphics are kept fairly basic, without just enough extra dithering and shading to give a comfortable sense of depth and familiar Vorticons atmosphere.
The coloured bricks as the predominant feature in most levels could perhaps have done with a bit more highlighting. This can be forgiven on the basis that the corresponding studs are, as far as I've seen, consistent throughout the game.
The story is pretty simple, with 4-year-old Billy Blaze (predating the original trilogy by about 4 years) playing with his brand new Christmas present, the "Turbo XL Maximus 10,984 Piece LEGO Set". He invents a hero for his new creation, Captain Keen, whose first mission is (of course) to rescue a captured princess from evil-doer Sir Icky and his camo-clad henchmen (with assurances that anticlimatic Super Mario antics will not ensue).
Level design is well executed, each one possessing a unique and intriguing well connected structure with excellent attention to background details and overall aesthetics. Hazards and enemies are well placed to provide a balanced challenge. Door puzzles are sometimes a bit too reliant on open-a-door-to-get-another-key, but that's cool because it forces you jump over more LEGO platforms to get to the next door.
Point items are mathematical symbols because reasons. (Ilsoap explained that he just couldn't think of anything appropriate and left it up to the imagination of the 4-year-old boy genius protagonist).
To be honest, I have blasphemously failed to actually complete this mod and can't comment on the overall experience (will get around to it one of these years). Nonetheless it is a classic piece of Keening history and 314% categorised as a must-play.