For the previous challenges I haven't had any problems, finding the correct tools for each challenge wasn't really hard. But #7 and #8 were stressing me out, not because the "developer part" but the challenge itself, as I needed to remember things and be fast.
But I think the tips website is really well made! And the challenges that weren't tedious were quite fun, as it was cool to see how the developer tools can be (ab)used to created challenges like these!