Oooooooooh...you could have mentioned that earlier
I see how that works; you don't hit a directed exit if you don't reach any exit at all. I never died during the countdown in level 3 because I cleared out every other robot first, that's how I didn't catch that.
Theres no easy way around that unfortunately.
Option 1: Put in another level in between level 3 and and the secret level, This extra level will have no countdown and only serves to direct you onto level 4, either that or you game-over in it. This option instills the least change except for this random unexplained 'bonus level' that appears out of nowhere and does nothing unless I can make up some way of weaving it into the story
Option 2: Re-instate the D2 style secret level (which is a serious pain in the ass because it is easy to die in the secret level and get booted back to Level 3 constantly) this is the simplest option but I'd rather not do this
Option 3: Remove the reactor in level 1 (you can pass the level without blowing it anyway) and shift the secret level in between level 1 and level 2. I can make up lame excuse in the briefing that explains why there isnt one there. Sounds feasible but what happens in multiplayer?
Option 4: Bother karx about coding in another feature that lets you skip entire levels
Option 5: Shift the secret level to the end and have the exit in level 4 point past the secret level (level 6, but I am not sure if that would actually work), that at least prevents the explotability of the bug but if you get incinerated in level 4 you just get the same bug there instead.
In the meantime enjoy your free trip to the secret level, which you probably arent because the secret level is sadistic hellhole of pain and suffering MUAHAHAHAAH!
I kid, I kid
I thought of something else, what if it was possible for a directed exit to point to a [D2 style] secret level? If the secret level was linked to no other level, would you still get booted back to another level if you die in it?