10 Amazing Video Games You Should Only Play Once

10. Portal

Valve's Portal is one of the most iconic and influential puzzle games of the last 20 years - a mind-bogglingly creative physics-based puzzle-platformer that also touts a singularly eccentric, infectiously charming sense of humour.

As enormously satisfying as the moment-to-moment gameplay is, though, there's not a huge incentive to replay Portal because, this being a puzzle game and all, the fun is largely centered around solving problems with your portal gun.

Those euphoric lightbulb moments of figuring out a tricky test chamber simply can't be replicated upon repeat playthroughs when you're already equipped with the knowledge to progress, especially as the solutions themselves tend to be incredibly memorable and may not be forgotten by players for years and years.

Unless you're a speed-runner determined to bend the game over your knee and dismantle it as fast as possible, there's very little incentive to play it more than once, as masterful as it is.