That does sound like a battery issue. The green batteries that come with the Ugobe pleos aren't very good. They are old and seem to die. It may be possible to extend the play time by reconditioning the battery. Just charge it till the charger light goes green then take the battery off and put it straight back on to charge again.Keep doing this until the battery goes green straight away when you put it back on charge. Then run it through the pleo and see how it goes. It should hopefully give you more than the 10mins your getting now.
I would recommend getting an egg battery and charger. They are a much better battery and give a two hour play time. You can get them from the stores here on the forum or also on ebay.
Try the reconditioning and let us know if it helps
As for the walking backwards but not forwards I thin you just haven't had enough time with him running to really judge if there is an issue. They will walk backwards if they have an obstacle in front of them or if they think they see the edge - like the edge of a table or my guys will back up if they are on the tiles in the bathroom as they think the lines between the tiles are edges in the floor
So it could just be that. Also Ugobe pleos wont walk if they are getting attention
You could try leaving him alone for a few minutes and see what happens.