The Atom cpu's Cherry Trail x7 integrated graphics is a low end integrated graphics. Clock speed @ 200-600MHz vs the
Intel HD4000 @ 350-1359MHz (the oldest intel HD graphics that has dedicated Win10 drivers).
The Cherry Trail gpu should be able to run COD-AA, but you may not be able to use all high settings.
Runescape. I'm not so sure. The original from 2001 yes, but the current version maybe not ?
- You may be disappointed by the limitations of the Cheery Trail gpu. I reckon it would be better to wait and save
for a tablet with an i3 or i5 with UHD 630 (clock speed - 350-1150MHz) as, Dave suggested.
The AMD cpu's with integrated graphics are also worth a look as they generally offer better value for money.
I believe some of the newer AMD igpu's have better performance than the current Intel UHD graphics.