An accelerated stall, in the real world, does indeed result in an altitude loss, though it is slight if recovered from instantly. If you do not recover immediately, then the altitude loss is greater. If you don't recover for thirty seconds, then the altitude loss will be very great indeed.

In the real world, under the right conditions (a high-performance fighter would probably have to be at a somewhat reduced throttle setting so that the rudder authority is as strong as the engine torque), you can at any speed yank the stick back into your chest and hold it there, and with proper use of rudder the aircraft (assuming that it's not one of the few which have a poor wing design) will fall, fully stalled, straight forward. The U.S.A.A.F. termed it "falling directly away from the pilot." "In an accelerated stall with the ball centered, the airplane will fall directly away from the pilot," and "It will stall straight forward even in an accelerated stall" are similar quotations.

Obvously, ball centered isn't the only condition. The aircraft's lateral weight should be balanced; flaps and gear may need to be raised and external stores may need to be gone; ailerons must be in the correct position; the aircraft must not have more torque than the rudder can counter (this is not a concern with counter-rotating propellers, obviously); et cetera.

As for IL-2, unless they drastically changed the flight model after version 4.04, a straight-forward stall isn't possible under any conditions in the Lockheed P-38, except for power off (which is ridiculous because the P-38's counter-rotating propellers counter each other's torque). The real P-38, by all accounts, had no tendency to drop a wing in any type of stall. It would stall straight forward even in an accelerated stall, according to numerous sources (including training materials).

And not even the spins were right. Anyone who has spent a fair amount of time closely studying spinning aircraft can see that. In that game, the "spinning" aircraft simply rotate about a single axis as if they didn't have wings, but were simply set in motion and possessed no friction.