According to this here website, the Japanese version of Time Gal supposedly contains--yes--a topless image of the main character, Reika (it turns out her name is not actually "Time Gal") after the end credits if you can beat the game on hard. I figured there was also something about doing it without dying too. (Actually, looking it it now I'm having trouble getting any meaning out of that statement on the webpage at all) Anyway, I obtained a Japanese copy of the game while in my recent travels, so now I can confirm that this is totally NOT TRUE, and the game contains no at all.
I did make this animating gif, however, depicting everyone's favorite miss animation, wherein Reika's pants are ripped off by a phallic-shaped purple reptile.
Was it released in America? And if so, What was it called?
It was originally a mid-80's arcade game from Taito and a group called Wolf Team (hence the thick 80's anime style). I think it may have been released on PC-Engine before, but it wasn't released on the Sega CD until the early 90's, with some visual cutbacks. I believe that was the only version released in the US, under the same title, Time Gal. We didn't get an arcade perfect version until just about six or seven years ago on the PS1, and that was only released in Japan.
It's an FMV game so it really isn't very good, but the green-haired chick is hot. She looks like Lum. Maybe those boobies were only in the arcade version?
I'm pretty sure there's no PCE port, but there's a Saturn port that came out alongside the PSX version. They both include the (also ported to SegaCD) FMV game Ninja Hayate along with Time Gal.