Jewels 20

A 1-kilobyte game (coded for the MiniGame Compo coding contest) for the
unexpanded VIC-20, Jewels 20 is a puzzle game based on the same concept as
Bejeweled. You have two minutes to eliminate as many jewels as possible from
the playfield by swapping a pair of jewels around, forming a row of three or
more of the same colour. Swapping pairs is only possible if the swap will
result in same-colored rows. As the rows are formed, they disappear, and the
jewels above fall down, with more coming in from above, making this an endless
game were it not for the time limit. For each eliminated jewel, you score 10
points, with bonus points given for arranging Puyo Puyo-style chain reactions.

Jewels 20