The Wargamer has a review up of the email tactical shooter, Laser Squad Nemesis. The creators of the game are the very same who did X-Com so I would imagine it's well worth looking into. Here's what Veloxi had to say about it:
Games by email may be an excellent solution to those of you who go to work but don't actually want to work. Anything to stay sane I always say!
Laser Squad Nemesis isn't going to blow you away visually or audibly, but it does well considering how small the program is. The graphics are well done, colorful, and detailed. Units are easy to pick out against the various backdrops as well. Laser Squad Nemesis uses 3D acceleration to an extent, allowing you to zoom in and out effortlessly. The graphics themselves are exclusively 2D, however, but this doesn't detract from the game at all.
Audibly, this is Laser Squad Nemesis only real weakness, in my humble opinion. Besides sound effects depicting weapons, explosions, and movements, there's little else to audibly draw you into the game's universe. I can see where this would be a compromise in order to keep the download small and the e-mail files light, but it was missed.