A number of balance related issues have been addressed:
Flybot Generator Delay
The flying robots that appear in some of the later levels of the game will now take a bit longer to respawn. Previously, a new flying robot would be respawned immediately after one was destroyed. Now there is a bit of a grace period, to give players more room to maneuver before getting attacked again.
Weapon Respawn
If a weapon appears on a particular level, and you use that weapon, and deplete all of its ammunition, the weapon will now respawn. This was always true for the default gun and timebombs, but it is now true for all weapons. This will help especially with later levels where enemies can take more hits, and some enemies respawn, like the flybots mentioned above.
Weapon Ammunition Increase
Some weapons will now start with more ammuntion. The default gun, machine gun, laser rifle and rocket launcher will now start with about twice as much ammunition loaded. However, if you are playing in hard mode, the original amounts remain.
Passable Spikes
The spike traps were passable objects that one could not shoot and that enemies and other objects could pass right through. This did not seriously effect gameplay, or so we thought, until it turned out that enemies could see through these spikes and also shoot at the player.
Spikes are now "solid" objects again, and this should no longer happen.
Alarm Volume
It was pointed out that the alarm that goes off when the player gets a Paradox Triangle could not be silenced by adjusting the game volume. This has been addressed, and it should no longer cause anyone any trouble.