Retrobot's favorite: Score Attack games

Volfied (Taito 1989)
Simple concepts are often the most playable and Volfied proves this. It's an ancient Taito arcade game, but you can find it on PS2 on the Taito Legends 2 compilation pack. The gameplay is essentially the same as Qix (also by Taito) but with improved graphics and more varied enemies to defeat.

The game is simple. You move around the outside of the playfield and can break into it to draw a line. Make it back to the edge and the line becomes a solid area. While drawing a line, the player's trail is vulnerable to attack. Make it back to the edge and you're safe again. Once 80% of the playfield has been claimed by the player, the stage is complete.

The challenge comes from completing each area with as high a percentage as possible. Forcing the massive enemy into a small corner (shrinking it in the process) can allow you to clear a much higher percentage of the playfield with your final line. Watch the vid, which demonstrates a perfect 99.9% clearance. The extra score awarded for the final increments of space is massive, so you've really got to take risks to get the biggest scores. It's one of the most addictive games Retrobot has ever played and one any serious gamer should try.