Connor Beaton writes: "Well this is a surprise for sure: we're only on our tenth article, yet this is the third game developed by Valve Corporation we've featured so far, which stands testament to the great innovation in its games that Valve continues to display in every single release. Portal was initially only released as part of Valve's The Orange Box compilation, which also included Half-Life 2 and Team Fortress 2, but was released stand-alone on the hugely successful Steam digital delivery service (which Valve also developed). While short, Portal's fantastic puzzles, atmosphere and humour make it a brilliant game regardless."