Do you mean to say that if you research Shamans as your first thing, that blocks you from Tier 4 research?
I think Nuju just meant that you have to have researched Shamans before you would be able to research Charm. You would have to have researched some of the unit types, though, so that couldn't be the problem for the entire master category.
EDIT: You need to research something on the Expert level to get access to the Master level.
With just the hunter unit researched, I didn't have access to any Master level research. If I researched A Bird in the Hand, for example, I could research teleportation for the hunters, as well as juggernauts and bomber balloons. Researching Devastators unlocked those 3 Master level items, as well as the On The Double devastator upgrade.
-BUG-Before battle I cannot choose Hostile AI setting at all
With this beta (or at least this is the first I've noticed it), there is no 'Default AI' setting, the difficulty level is just set at whatever the default value is in the main options. You should still be able to change the AI difficulty in the lobby, though.
