Master Of Orion 1 & 2 | GOG | £1.19 (so cheap)

Many latter-day 4X games have tried, but none have quite managed to unseat Master Of Orion 2 as the best space 4X title of all time. It really is superb, as you'd expect from Microprose and SimTex in their prime. £1.20 is also incredibly cheap, netting you the original game as well for all you retronauts.

Master Of Orion 3 isn't included in the bundle, which is fantastic news.