Steam – What’s the difference between “Free” versus “Free to Play” on Steam

Half-Carries or Semi-Carries are heroes that have the potential to carry the team in mid and lategame but will lose most likely to any "hard" carry.

The difference is the fact that a semi-carry has a better early game (escape mechanism, better farming tools, more teamfight potential for mid-game and overall more flexible[movement and items]) resulting in a much faster scale to late-game.

Examples of semi-carries are:

• Mirana (she can dish out a ton of damage but can also gank, solo, farm with spells, etc)
• Queen of Pain (aoe spells to spam and farm, ganking , solo) simply carries the team till late [when magic dmg isn't relevant anymore] and then pass the role to the real (hard) carry.

compared to hard-carries:

• Faceless Void (needs a babysitter, has no teamfight potential until he has his core items, no aoe spells to farm creeps)
• Spectre (same as void)

Furthermore the hard-carry has a ability that scales incredible well in late game (semi-carry lack these). For example: void - backtrack + time lock; spectre - dispersion + desolate; weaver - geminate attack; morphling - morph + adaptive strike; naix - feast + rage.

There is no way to get free games to stick in your library if they are not installed as far as I know.