Just finished the first episode. Can do it in around 2 hours. As said before elsewhere, its got lovely visuals, keyboards controls are few and easy to master. Got stuck a couple of times, couldn't work out what to do next but you don't need to be Einstein to figure it out. Linear, lots of save checkpoints so you don't need to back track for long when you die.
Jumping ledges can be a little problematic for slow fingers and there are three timed puzzles, again you need to be pretty quick running/climbing ladders. Has religious theme for the puzzles. Do you know your bible?
Think $19.90 is a bit steep. Big Fish prices would be more reasonable. May buy future episodes if BF are going to sell it.
In conclusion I did enjoy it, shades of Indiana Jones.
Hope this helps.