Sp.A.I is a visually stunning 3D game built using the Unreal SDK by five students at Queensland University. The installer installs SDK support, so you do not need a copy of Unreal itself to play.
The world is a Tron-like framework of glowing graphics, which avoids the necessity of creating textures and makes any polygonal artifacts explainable as part of the 'cyber world.' The back story is that you are a sort of cyber agent named Aiva (whom you see in the inevitable ass-cam) penetrating a computer system; apparently "hacking" means navigating through a 3D space, solving block puzzles, and platforming.
The puzzles themselves are nothing novel, although many of them do involve a timing element -- e.g., once you destroy one block, you must quickly destroy another, or a moving laser sweep will trigger an alarm. Thus, even though the gameplay is mainly puzzle-based, there's a skill-and-action aspect to it as well. Similarly, once you obtain a 'file' enemies will attack you, and apparently you cannot both carry a file and shoot back at the same time, so you must move quickly (and can use the file is a sort of shield). You do have hit points (which regrow once out of immediate danger), so it's not a "one hit kills" kind of game.
Platforming controls are, alas, kind of muddy, which combined with the fact that Aiva sort of floats along over the cyberspace often makes it hard to time your movement just so, and you may wind up over- or under-shooting targets at times. The platforming challenges are far from masocore, though, so the muddiness is tolerable, if still frustrating.
Nice tutorial, nice music; only a couple of levels, but pretty polished for a small student team.