All signs and secrets

[Goser]

anybody knows what happens if you catch all signs and shoot the credits guy at the end credits through the whole level?

Here´s a quote from Basost

引用自 Basost：

At the end of the credits there's a sort of leap of faith with a seemingly unreachable platform at the right side of the screen. Turns out you can take the immortal enemy with you from the start of the credits all the way to the right, shooting him across the gaps.

It took some effort but I got him there. After a bit an elevator comes up that takes you up (better to shoot him off the platform while you wait or he'll kill you). The elevator takes you up. There you can pick up the knife and kill some more enemies and a message appears that you need to collect the 45 signs to unlock the knife in the normal game. I hadn't at the time. The enemies killed me at that point, not sure if there's anything more?

[ItalianBungaBunga]

After collecting all the signs you unlock the knife. Nothing more it seems.