So, body didn't work and mind just went splat - so what's a fallen angel to do? There's one more wall to try to breech - the spirit.
Satan figures Jesus for a 'big picture' sort of guy. This messy incarnation thing is a means to an end - not an end in itself. Satan knows that. So, what if there's another, less painful, way to get to the whole 'ruling the world thing'? Wouldn't that be a fine little carrot...
So, up to the mountain top and a grand view of all the nations of the world. This is what it's all about, right? For whatever reason Jesus cares about these human/worm things - well, as ruler over them all He can make a great little world - a regular slice off the Paradise pie. No humiliating cross necessary - just walk right in and take over. And it just so happens Satan is running a special on world domination this week. Just worship Satan, here and now, and it's a done deal.
Personally, I suspect this is where Satan came closest to being tossed off the mountain and straight back to you-know-where... But our question is, was Jesus even really tempted? The answer is yes - the prize is too great not to be a temptation but Satan overplays his hand. Jesus is tempted but He is also instantly aware that Satan is trying to separate Him from God. Incarnation is messy, painful and ultimately humiliating - but it's also necessary for God's game plan to work. Falling down to worship Satan ain't a 'baby step' - it's a leap away from God - a leap Jesus has no intention of taking.
Jesus chose to come into the world. Here He chooses to complete that work. In both cases He is supremely aware of the cost - but He is also aware of the prize. God's plan gets Him both the humans He loves and is willing to die for and maintains His relationship with God. Added bonus, now His children can know He really does understand what temptation is like.
Satan's 'plan' gets Him neither. Sans the Cross, there can be no reconciliation so at most Jesus would rule the physical world for the short time (relative to eternity) before it decayed fully to death. Then He would be left with nothing at all.
Turns out Satan's biggest carrot is rotten to the core. But of course, so are all his carrots. Satan ultimately offers only death, destruction and the horrible loneliness beforehand. God offers life, love and goodness. Satan's offer is wrapped in pretty paper and has a big bow. God's comes in a glass box so you can see exactly what is involved. Satan's offer is pretty on the outside but hideous on the inside. God's offer doesn't look like much on the outside but is nothing but beauty within. Satan offers an easy street to destruction; God offers a difficult path to life.
Come to think of it, when we really understand what Satan has to offer, it ain't so tempting after all...