Omikron: The Nomad Soul is on sale for $2.50 right now on Steam. It's a very underrated game in my opinion, and plays like a mix of Shenmue, System Shock 2, and Deus Ex. If you buy it, be sure to check, and if necessary, rebind all of the controls. Also, be patient when setting your resolution. There's no "Apply" button, so every time you switch through the options, it changes your resolution to that setting.
The game is also available on the Dreamcast, and can be found on the ISOZone, but I've never tried that version and it requires 99 minute CD's if you want a perfect rip.
Steam version - http://store.steampowered.com/app/243000/
99 minute DC version - http://www.theisozone.com/downloads/dreamcast/dreamcast-isos/omikron-the-nomad-soul-99min-perfect-rip-eur/
80 minute DC version - http://www.theisozone.com/downloads/dreamcast/dreamcast-isos/omikron-the-nomad-soul-dcres/