Yay! I own three of those systems:
Philips CD-i
Mattel Hyperscan
Tiger Game.Com
N-Gage I've played, it's horrible. Great concept, but oh so poorly implemented. Screen is entirely to small and the resolution is hideous, the control button scheme is a nightmare, and the game card insertion requires turning the phone off and removing the battery.
Halcyon - There's a video segment on an episode of The Computer Chronicles, hosted on archive.org, featuring Halcyon and it actually looked like a rather interesting system. First game system to ever have built-in voice command. See video:
http://www.archive.org/details/Lasersan1985Game.Com - Actually a really good concept for a system, but what really killed it was a poor screen refresh rate. I think it topped out at 20fps, which was really noticeable in any action game. Otherwise it has good sound quality, good built-in features, and good ergonomics. Tiger succeeded in getting some top publishers signed on to make games for the system as well, such as; Sega, EA, and Miday, plus their own in house programming team. It was also the first handheld game system to feature:
- Touch Screen
- Stylus
- Dual Game Cartridge Ports
- Built-in game (solitaire) and other features.
- Internet Connectivity (using optional accessories)
Hyperscan - Just purchased at a yard sale this year. Have yet to even try playing it.
CDI I think deserves to be on that list. There are no truly memorable good game titles for the system, aside from the arguably horrible Nintendo titles. The system didn't do anything new from other CD-based systems of the era. Only noteworthy thing about it was the optional MPEG decoder expansion module for the original versions of the system that allowed the unit to play Video CD's, though that media format never made it to North America as a mainstream commercial format.
Virtual Boy is a revolutionary game system which was unfairly killed before it ever launched good by biased bad press coverage. I own a Virtual Boy and I can honestly say it's one of the best game systems Nintendo ever made. The problem was that if you were someone with epilepsy this system would, not might, induce seizures. What the news media failed to report when saying the system was dangerous was that all of the people who had been negatively affected by the system were confirmed epileptics.