Armed group of terrorists took over Chernobyl power plant and surroundings. They threat to blow up the reactor sarcophagus if not paid enormous ransom. Only one man was chosen to infiltrate terrorists and destroy detonators... you.
Chernobyl Terrorist Attack is definitely a budget game. Everything from the plot to the graphics to the voice acting screams budget. That said, I did enjoy it, and the AI seems to be smarter than most people credit. Enemies flank, use grenades (although not to much effect), don't always pop up from the same bit of cover, and I've even seen them retreating back to the next encounter at times. I'd probably even rate them above the AI in games like CoD or Battlefield.
The graphics, in general, would have looked spectacular in 2004 and okay in 2005. The models actually aren't too bad, but the textures are really low resolution and repeated. It's not as good looking as IM, Overdose, Overgrowth or any number of indie games, but it's not horrible to look at. Just remember to turn motion blur off.
The game's short, the plot basic, the voice acting amusingly bad and the gameplay pretty generic. Still I enjoyed the game, liked the fact that the protagonist wasn't American and like the fact that nearby explosions blur vision and smoke actually obscures your view and sticks around for a while. Normally I'd have rated it 6/10, but the game was made by just seven people, is self funded and was probably made in a couple of years, or thereabouts, with the developers probably also taking work outside of the game (their old website stated that they were available for such work), so I'm going to bump it up to a seven.
TL:DR - I enjoyed the game and don't regret spending $10 AU on it. Some of the criticisms leveled at it are probably unjust, or perhaps may simply be because of different experiences. Try the demo and, if you like it, be sure to buy the game!