The early access has 12 class ascendancies. They are promising to later have 36 class ascendancies.

The early access campaign has 3 of the 6 acts completed. In the early access, you will level 1-45 in Act 1-3. Then from level 45-65, you replay Act 1-3 but with levels scaled. Then at level 65, you enter the endgame ie exploring the atlas.

The early access POE 2 end game has over 50 bosses, over 400 monster types, and 7 playable end game systems. The atlas system is entirely reworked.

Any in game purchases that you made in POE 1 are transferred to POE 2 and vice versa.