For players who frequently switch between playing Descent and Imperial Assault, what are the most commonly forgotten rule differences?

For Example:

Descent: Hostile figures block movement unless an ability supersedes it

IA: Hostile figures are treated as Difficult Terrain (1 extra MP per space moved through)

Are you looking for this?

https://boardgamegeek.com/filepage/134544/differences-between-descent-20-and-imperial-assaul

I'm just getting into Descent now (got the core on Friday) so this should be helpful.

Thanks!