This is one way to do it
with cte as
(SELECT
ROW_NUMBER() OVER (PARTITION BY table.name ORDER BY id) row,
name,
score
FROM table)
SELECT
a.name ,
a.score - ISNULL(b.score,0)
FROM
cte a
LEFT JOIN cte b
on a.name = b.name
and a.row = b.row+1