A playable demo for Europa Universalis IV is now available on Steam, alongside preorders of Paradox Development Studio's strategy sequel that's due for release next week. The full game will offer multiple language support and cross-platform play between Windows, OS X, and Linux, but the demo is just for Windows and is only in English. This page offers a detailed description of what to expect from the demo, and here's a short summary:

In the demo version of Europa Universalis IV, players can take up the flag of one of four available nations, sampling the trade system as Venice, going to war as the Ottoman Empire, founding new colonies as Portugal, or engaging in shrewd diplomacy as Austria. Demo games will last for 28 in-game years and include an extensive tutorial and hint system. The demo will not include multiplayer capabilities, and please note that the abilities to save & load have been disabled.