Just saw another observation in a game review that really isn’t all that specific to the one game they were reviewing. In this case, it was a CNet review of the game, Alpha Protocol, by Obsidian Entertainment. A few of the observations about the AI wereÂ corroboratedÂ by other reviews elsewhere, but this one is the most detailed. (Most of the meat about the AI is on page 2 of the review.) The author doesn’t dance around the issue, either:
The AI is pretty dreadful. Security agents and mercenaries run about the levels in haphazard ways, may start climbing ladders as you fill them with lead, will kneel on top of exploding barrels, or might stare directly at you but fail to react unless you take a shot or give them a good punch. There’s a weird sense of randomness to your enemies’ behavior that diminishes the impact firefights may have had.
This is a common series of complaints about modern game AI. 10-20 years ago, this is mostly what we expected. Actually, to correct myself, what we usually got was enemies that turned to face us and then moved toward us in a line until we mowed them down. In the days of Doom and Quake, that was OK. Today? Not so much. Running around randomly provides a sense of activity and motion but immediately begins to trigger our sense of wrongness about the situation. This is especially noticeable as the dichotomy between excellent graphics and poor AI spreads. In any enemy that we can remotely anthropomorphize, this effect is even worse because we have an image in our head of what a human-like character should be doing in any given situation.
Where I would like to diverge from the author of the review is in the word “random”. We need to be careful with that word. Both in my book, Behavioral Mathematics for Game AI and in a number of the conference lectures I have given on the subject, I speak about the benefits of using randomness to provide variation in behavior selection. Games of all types are beginning to use these techniques as well.
For example, Richard Evans (Maxis) has spoken numerous times on the decision model for the Sims 3. The Sims go about a process of rating all the available behaviors and scoring them as to how well they match what the Sim wants or needs at the time. Then, they select from the top choices using what we call a “weighted random”. All of the actions are “in play” proportionate to their score, but the better the selection, the more likely it will be chosen. Is there randomness there? Yes, to provide variation. Does it look random? Not really. The reason is because each of the potential selections is actually fairly reasonable at the time — the result of the scoring system. To us as observers, we don’t view this as “random” — just “interesting”.
On the other hand, it seems that the behavior selection in Alpha Protocol looks random to the observer because either:
- The behavior selectionÂ is, indeed,Â random, or
- The behavior scoring algorithm is so poor that it doesn’t properly give the advantage to reasonable-looking actions.
|Often times, behaviors will be chosen without consulting the current world state.|
Either way, something is amiss. There is a 3rd option here as well. Often times, behaviors will be chosen without consulting the current world state. The “climbing ladders while you’re filling them with lead” bit might be an example of that but the observation where the enemy is seemingly unaware of you is a much better example. The bottom line is that the hardest part of designing AI is providing the adequate knowledge representation of the world state so that we can reason on it and make contextually appropriate decisions.
From a gameplay standpoint, the behaviors above can lead to some serious disappointment. To go back to the article:
Yet Alpha Protocol is no more a proper stealth game than it is a shooter. As with the shooting, the inconsistent AI provides a major hindrance… [snip]… Sneaking up on an enemy and taking him down with a minimum of fuss is mildly rewarding, as it tends to be in most games. But the actions you take leading up to that point involve activating certain skills and scurrying around in your silly crouched position–not outsmarting sharp AI or using the environment in clever ways.
|With a generally random-acting AI, we aren’t outwitting anything.|
We have had enough stealth games under our belt as an industry that we have primed the consumer with expectations of what to expect. Games ranging from Thief to Splinter Cell have shown us that the best part of stealth games is not just surprising an enemy… but outwitting him when he is actively trying to prevent you from surprising him. With a generally random-acting AI, we aren’t outwitting anything. The “surprise” aspect of it comes from merely staying out of his view. For all intents and purposes, that gameplay mechanic goes back to arcade shooters from the early 80′s. Haven’t we grown out of that yet?
Unfortunately, in a throw-back to my column earlier this week, the review goes on to compliment some of the other production values (though not nearly in as glowing of terms as the review of Lost Planet 2:
Alpha Protocol is not ugly, however; it’s just behind the times and artistically uninspired. Nevertheless, the safe houses Mike operates from between missions have some nice views, and some of the outdoor missions throw in some welcome flashes of color. Similarly, the sound design gets the job done, though without much style. The voice acting is at least solid, and the generic action-movie soundtrack ramps up at the right moments but otherwise stays out of the way.
Congratulations, I suppose. The problem is, our consumer public wants more than pretty pictures and nice sound. They are getting used to all of that and are now complaining about things being dumb. Again, this goes well beyond Alpha Protocol. This review can be copy-and-pasted to other games in as much of a templated fashion as trashy romance novels. There are way too many games that are missing the boat on this. Granted, as I mentioned in the Lost Planet 2 column, good AI developers are increasingly hard to find. That may be the case with Obsidian. I don’t know. (What I do know is that it’s time for me to give a ring to their HR guy.)