It runs great, and everything looks nice, but without challenging, well thought out puzzles and quality writing it doesn
The other key thing for an adventure game is puzzles. Tunguska fails at this as well. The puzzles are of the super illogical type, and with only a few easily identifiable (thanks to the handy hotspot locater button) hotspots per screen, the gameplay pretty much consists of constantly attempting to use or combine every item in your inventory. It never forces you to think about how to use your items as a good adventure game will. One thing I did like though, was the character swapping feature. At one point in the game, one of the characters was locked in prison, and the other character was trying to get her out. They ended up rigging this string through a drain pipe, and you'd have to exchange items between the characters. I found this kind of interesting. It's a shame they couldn't have done more with it.
Graphically the game is pretty nice. The pre-rendered backgrounds are vibrant and detailed, and everything runs very smoothly and the game seems to be quite stable. It's kind of interesting, the strengths and weakness of Tunguska are kind of the exact opposite of Broken Sword 4. Whereas Broken Sword 4 had quality writing, voice-acting and puzzles, it also suffered from dull, sluggish graphics and quite a few technical problems. The reverse is true with Tunguska. It runs great, and everything looks nice, but without challenging, well thought out puzzles and quality writing it doesn't really matter.