"Why would you think any of this was a good idea?" "Probably cause I'm a dangerous sociopath with a long history of violence" "Oh" "I don't understand how you keep forgetting that" Probably one of the best phrases of history
Aside from the already pointed out missing power and toughness for the creature, there are a few other things I would like to point out. When making an effect, activated abilities that use a tap symbol always have mana symbols before the tap symbol and additional effects after the tap symbol. That being said you're effect should read as: T, Sacrifice two lands: [Effect]
For the actual content of the effect, it just needs a little wording tweak: T, Sacrifice two lands: Destroy all other creatures. Put a 0/1 black Horror creature token named "Flying Face" with flying onto the battlefield for each creature destroyed this way.
Don't need to say on the battlefield for the destroy effect as you cannot destroy something not on the battlefield already. Flying and Face are not creature types, so at best could maybe change to what I did, make them Horrors or maybe even Nightmares, whatever suits your fancy, and have them just be named Flying Face.
Other than that, the card is alright, a bit overpowering to some, but eh, I wouldn't worry about it in a real game myself. Just a thought.