Your photos are not very clear for a good illustration but the tree is more dead than alive, unfortunately. All of the top portion appears dead - dry looking, silvery-gray wood - and should be removed. Also where it appears lower on the tree. That just leaves you with a few lower branches that appear to be still viable, so the form and habit of what should be a gracefully mounded or layered weeping laceleaf has been permanently altered.

Under other circumstances, the suggestion would be to just get rid of the tree or at the very least, plant somewhere where its distorted and stunted habit will not be an eyesore. And if you are not experienced in growing JM's in a container, this is a very challenging way to grow any Japanese maple and is prone to all manner of difficulties, including what to do with the tree over winter, depending on where you are located. These are happiest in the ground and require the least amount of attention there once established.

It is your choice how you wish to handle this tree going forward. It is never going to look great or even 'normal'. I'd be inclined to replace it with a similar but healthy specimen and pretend that it is the same 'gifted' tree should anyone ask ;-)

Two great articles (from the CONTAINER GARDENING forum here on GW) you can read will teach you all that you need.

Container Soils Water Movement and Retention

and

Trees in Containers

Thanks guys. And yeah, it's pretty much dead above the one or two lower branches. I might find it a spot in the yard to plant it. I have learned a huge lesson, I am never going to give people plants as presents! It's so devastating when you kill them!

I agree with everything gardengal wrote, and would add that the tree's root flare appears to be buried beneath a layer of fine roots, which is not good. Root surgery should probably be done before repotting or planting. The fault for this problem lies with the nursery that sold it, not you. If you know someone with a knack for gardening and more time on their hands, you might ask them to rescue your tree, or I see a sad future for it, unfortunately.