valve intro level up hl2 xp
The guitar riff from valve game intros as the level up sound and the button access granted sound from half life 2 for xp.
button – https://www.youtube.com/watch?v=Ak7A2Q_LKac (15 seconds in)
valve intro – https://www.youtube.com/watch?v=c__UOCIMe74 (2 seconds in)