I've noticed that no matter what level you have in a designated skill, it doesn't seem to correlate with the roll requirement. I have 11 in infiltration and I'm required to roll 18, and I actually roll a 4? This issue needs some reworking.
I also have a very short attention span so the guess and check nature of the game turns me away after five minutes. Make maybe checkpoints or more rerolls. Or even make it so you can roll a few time before ultimately failing.