If them being playable on the GT is a must, you're going to want to go for titles with bigger sprites as the screen on those things are just goppingly awful. I was playing some games on one I had a couple of weeks back before it went to eBay, and had forgotten just how awful they were. What I did play on it that still worked reasonably that you could pick up under your budget were things like the first PC Kid, Chase HQ and Klax.
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