best steam games for under 20 pounds

Im bored and need entertaining, so any good games that don't have too high a lurning curve.

Before anyone says it I own:

CS 1.6
CSS
TF2
HL2 (and all episodes)
L4D2
and some others

Also my pc isn't really powerful

my specs are:

Intel Pentium Dual Core@3.2gHz
1.5gb of RAM
NVidia GeForce GT 240 (1GB)

super meat boy

fear 1

guildwars prophecies/factions/nightfall

If you have a controller get super meat boy.

Batman: Arkham Asylum is fun, and it's really cheap. It's not that demanding either, so you should be able to run it.

super meat boy

fear 1

guildwars prophecies/factions/nightfall

ionusX

Batman: Arkham Asylum is fun, and it's really cheap. It's not that demanding either, so you should be able to run it.

RaseshX

Already got and completed on the xbox, very good though :)

That is $32 when converted to USD. You can't go wrong with Guild Wars, Dungeons of Dredmor, Bloodlines, Mount & Blade Warband or the STALKER games.

Well, they're all digital copies so they don't weigh anything.