GemRB is quite complete, especially regarding BG2, BG1 and IWD1 which can be played through. The whole Baldur's Gate saga is completable. There is of course still stuff to be done.
PST and IWD2 are not completable yet and require a lot more love to reach the level of the other games. Both can be played for several hours though.
There is also a work-in-progress demo in the repository, but it is currently not much more useful than the included minimal non-gui test demo.
iwd2: Chapter 0+1 completable, full spellbook and ECL support
multibyte font support (chinese, korean, japanese)
favourite weapon/spell tracking, bg1 dreams
most gemrb overrides were moved and are now moddable via game override
initial bundled gemrb demo stubs
random encounters and spawns (properly difficult)
iwd2 combat, stats, spells, skills, effects and actions
animations, speech, input
looting, worldmap, hotkeys (work everywhere), fatigue
bugfixes
Older changelogs