It's an old arcade-style video game in which you move around a 2D
plane (with acceleration-based controls like _Asteroids_, apparently);
in the center is your base. From the periphery myriads of attackers
come in blasting away at your base. The idea is to circle around and
destroy them before your base is. (I'm going on the description of it
I found in http://books.google.com/books?id=cDu85xT-5OUC - the hits
for software versions of Space Fortress all seem to be for only
tangentially related games.)
It's interesting because there's been a fair amount of research using
it, showing some benefits to attention etc. eg.
http://www.bcs.rochester.edu/people/Daphne/TCN_of_VGP.pdf
http://www.sharpbrains.com/blog/2007/02/08/brain-training-with-cognitive-simulations/
http://cat.inist.fr/?aModele=afficheN&cpsidt=17646815
Looks like a fun game anyway.
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gwern
I thought I'd mention: I have become dangerously addicted to _Grid
Wars 2_ (a more-strategic take on _Geometry Wars_, itself an updated
_Robotron_), and it fits the description pretty well, if you swap out
one base for 3 or 4 black holes.
You fight off waves of sophisticated attackers trying to kill you or
be sucked into the black holes, and you need all the skills of a shmup
combined with a general strategic sense (since a black hole can be
overloaded with enemies, blowing up, costing you the black hole - a
valuable defense - all the points you could've gotten if you had
destroyed it yourself, *and* unleashes a massive swarm of
unusually-deadly enemies straight at you, you need to dash from hole
to hole shrinking them down and occasionally destroying them).
Indeed, from one perspective, it's a twitch shooter in which you farm
black holes, stressing both your reactions and intuition about the
flow of battle; for a good review, see
http://worldofstuart.excellentcontent.com/grid/wars.htm
--
gwern
Yes, hard-mode is astonishingly difficult on both the tactical and
strategic levels. (And I say this as someone who recently beat _Ninja
Gaiden Black_, on hard.) I think I've maxed out at 300k. I only play
it because I don't like how long one must wait for the black holes to
show up on normal!
Part of the problem is that hard-mode likes to dish out 'cheap' deaths
- ones where an enemy or spawn-point is created *right* on you,
resulting in an instant death (I think the FPSers call this
tele-fragging). And then there are the mass spawns; I still haven't
figured out any reliable way to survive '50 high-speed homing circles
have instantly spawned all around you only 0.3 seconds away', besides
hope I can use a smart bomb in time.
Unfortunately, these cheap deaths reduce the value of Grid Wars as any
kind of training tool. If half your performance is due to simply the
Random Number God smiling on you... (And equally unfortunately, it
seems unlikely anyone will pick up the development of Grid Wars due to
the IP issues, so we can't look forward to this being fixed.)
--
gwern