We can tell from experience that the Halfbike is great for inclines up to 8%. Here you can learn more about it halfbikes.com/how-does-the-halfbike-perform-up-hill
Going downhill is quite fun on the Halfbike, but it should be done with great caution, especially when just starting. We'd advise going slow and see how it goes.
Since there is not particular shock absorption on the Halfbike (it is a city child), you'll need to keep you hands relaxed on the handlebar, that way they act as sort of absorbers to the sides and can help you get through uneven terrain. This comes with practice and you'll feel getting more and more relaxed on it.
The liquid sealant greatly reduces the risk of punctures (does not eliminate it completely) and that's the only thing it is used for.
Here you can see a video of the rider braking at full speed youtu.be/JrXHbh58oAQ
Here you can read a bit more of what you can expect from the learning curve and process www.halfbikes.com/learning
If you're interested in a test-ride, you can check on our map for ambassadors close to you and contact them directly www.halfbikes.com/playground